很多app的首页都会有一个用于显示热点消息的banner，通过垂直切换文本的方式动态展示消息。垂直切换的方式可以有效利用空间显示更多的内容，动态的效果也更能吸引用户的注意力。
实现这个效果，我能想到的方式大概有两种：
1、继承一个LineLayout，在里面添加两个TextView，通过动画实现TextView的移动、显示、隐藏。
2、继承TextView，手动去绘制文字，然后动态的改变文字的绘制，以实现切换的动效。
相比之下，第一种方式要简单一些，而且方法1不只可以添加TextVIew，还可以添加两个ViewGroup，然后构建更加复杂的布局，如添加图片等。为了体现自定义控件的特点，这里使用第二种方式来实现这个功能。具体看下代码的实现：
private static final int DEFAULT_SWITCH_DURATION = 500;
private static final int DEFAULT_IDLE_DURATION = 2000;
private Context mContext;
private List<String> lists;//会循环显示的文本内容
private int contentSize;
private String outStr;//当前滑出的文本内容
private String inStr;//当前滑入的文本内容
private float textBaseY;//文本显示的baseline
private int currentIndex = 0;//当前显示到第几个文本
private int switchDuaration = DEFAULT_SWITCH_DURATION;//切换时间
private int idleDuaration = DEFAULT_IDLE_DURATION;//间隔时间
private int switchOrientation = 0;
private float currentAnimatedValue = 0.0f;
private ValueAnimator animator;
private int verticalOffset = 0;
private int mWidth;
private int mHeight;
private int paddingLeft = 0;
private int paddingBottom = 0;
private int paddingTop = 0;
private Paint mPaint;
//回调接口，用来通知调用者控件当前的状态
public VerticalSwitchTextViewCbInterface cbInterface;
public VerticalSwitchTextView(Context context) {
this(context, null);
}
public VerticalSwitchTextView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public VerticalSwitchTextView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
mContext = context;
TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.VerticalSwitchTextView);
try {
switchDuaration = array.getInt(R.styleable.VerticalSwitchTextView_switchDuaration, DEFAULT_SWITCH_DURATION);
idleDuaration = array.getInt(R.styleable.VerticalSwitchTextView_idleDuaration, DEFAULT_IDLE_DURATION);
switchOrientation = array.getInt(R.styleable.VerticalSwitchTextView_switchOrientation, 0);
} finally {
array.recycle();
}
init();
}首先定义一些常量和变量，并实现了三个构造方法。
常量的含义可以直接看代码的标注，构造方法中只有一个参数的方法是在代码里使用new生成View的时候调用的，两个参数的构造方法是在xml中定义View的时候调用，三个参数的构造方法不常用，当有自定义style的时候会用到。构造方法中对自定义属性进行了解析，后面会用到。
<resources>
<declare-styleable name="VerticalSwitchTextView">
<attr name="switchDuaration" format="integer"/>
<attr name="idleDuaration" format="integer"/>
<attr name="switchOrientation">
<enum name="up" value="0"/>
<enum name="down" value="1"/>
</attr>
</declare-styleable>
</resources>上面是自定义属性的内容，分别对应于切换时长、切换间隔和切换方向。
private void init() {
setOnClickListener(this);
mPaint = getPaint();
mPaint.setColor(getCurrentTextColor());
animator = ValueAnimator.ofFloat(0f, 1f).setDuration(switchDuaration);
animator.setStartDelay(idleDuaration);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
currentAnimatedValue = (float) animation.getAnimatedValue();
if (currentAnimatedValue < 1.0f) {
invalidate();
}
}
});
animator.addListener(new Animator.AnimatorListener() {
@Override
public void onAnimationStart(Animator animation) {
}
@Override
public void onAnimationEnd(Animator animation) {
currentIndex = (++currentIndex) % contentSize;
if (cbInterface != null) {
cbInterface.showNext(currentIndex);
}
outStr = lists.get(currentIndex);
inStr = lists.get((currentIndex + 1) % contentSize);
animator.setStartDelay(idleDuaration);
animator.start();
}
@Override
public void onAnimationCancel(Animator animation) {
}
@Override
public void onAnimationRepeat(Animator animation) {
}
});
}init()方法中定义了一个属性动画，通过属性值的更新控制绘制的进度，在AnimatorUpdateListener的onAnimationUpdate()方法中，不断调用invalidate()，从而触发View的onDraw()方法回调。在AnimatorListener的onAnimationEnd()方法中，对要显示的内容进行更新，同时延时一定间隔再循环执行动画。
/**
* 设置循环显示的文本内容
*
* @param content 内容list
*/
public void setTextContent(List<String> content) {
lists = content;
if (lists == null || lists.size() == 0) {
return;
}
contentSize = lists.size();
outStr = lists.get(0);
if (contentSize > 1) {
inStr = lists.get(1);
} else {
inStr = lists.get(0);
}
if (contentSize > 0) {
animator.start();
}
}setTextContent()方法用于动态设置切换的文本列表，考虑到大部分应用场景下内容都是动态设置的，这里没有自定义属性提供xml文件的静态设置，如果有需求可以另行优化。
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
mWidth = MeasureSpec.getSize(widthMeasureSpec);
Rect bounds = new Rect();
if (contentSize <= 0) {
return;
}
String text = lists.get(0);
mPaint.getTextBounds(text, 0, text.length(), bounds);
int textHeight = bounds.height();
Log.d("viclee", "onMeasure height is " + mHeight);
paddingLeft = getPaddingLeft();
paddingBottom = getPaddingBottom();
paddingTop = getPaddingTop();
mHeight = textHeight + paddingBottom + paddingTop;
Paint.FontMetrics fontMetrics = mPaint.getFontMetrics();
//计算文字高度
float fontHeight = fontMetrics.bottom - fontMetrics.top;
//计算文字的baseline
textBaseY = mHeight - (mHeight - fontHeight) / 2 - fontMetrics.bottom;
setMeasuredDimension(mWidth, mHeight);
}onMeasure()方法中主要做了两件事：根据文本的高度、padding设置View的高度和确定文本内容绘制的baseline。具体baseline的原理和计算方法请自行google。
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (contentSize <= 0) {
return;
}
//直接使用mHeight控制文本绘制，会因为text的baseline的问题不能居中显示
verticalOffset = Math.round(2 * textBaseY * (0.5f - currentAnimatedValue));
Log.d("viclee", "verticalOffset is " + verticalOffset);
if (switchOrientation == 0) {//向上滚动切换
if (verticalOffset > 0) {
canvas.drawText(outStr, paddingLeft, verticalOffset, mPaint);
} else {
canvas.drawText(inStr, paddingLeft, 2 * textBaseY + verticalOffset, mPaint);
}
} else {
if (verticalOffset > 0) {//向下滚动切换
canvas.drawText(outStr, paddingLeft, 2 * textBaseY - verticalOffset, mPaint);
} else {
canvas.drawText(inStr, paddingLeft, -verticalOffset, mPaint);
}
}
}onDraw()中调用Canvas的drawText()方法绘制文本，根据我们设置的滚动方向的不同，绘制的y坐标的计算方式有所差别，向上滚动时，y值变小，向下滚动时，y值变大。需要注意的是，在调用drawText()的时候，x坐标为设置的左边距paddingLeft，y坐标不是控件的高度mHeight，也不能是字体的高度textHeight，只能是text的baseline，这个大家可以自己验证一下。
//回调接口，用来通知调用者控件当前的状态,index表示开始显示哪一个文本内容
public interface VerticalSwitchTextViewCbInterface {
void showNext(int index);
void onItemClick(int index);
}
public void setCbInterface(VerticalSwitchTextViewCbInterface cb) {
cbInterface = cb;
}最后提供了一个接口，通过回调通知调用者View的状态更新（切换到新的内容或者当前内容被点击等）。如果需要其他功能，可以根据自定义View的原理自行扩展。
＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝＝
2016.8.16更新：
增加gravity属性，水平方向的gravity属性可以设置为left、right、center，分别表示文字左对齐、右对齐和居中对齐。
增加ellipsis属性，可以设置为start、end、middle，分别表示当文字长度超出View长度时，在头部、尾部、中间显示省略号。
核心代码分析：
private void generateEllipsisText() {
if (ellipsisLists != null) {//防止重复计算
return;
}
ellipsisLists = new ArrayList<>();
if (lists != null && lists.size() != 0) {
for (String item : lists) {
int avail = mWidth - paddingLeft - paddingRight;
float remaining = avail - ellipsisLen;
if (avail <= 0) {
ellipsisLists.add("");
} else {
float itemWidth = mPaint.measureText(item, 0, item.length());
if (itemWidth < avail) {
ellipsisLists.add(item);
} else if (remaining <= 0) {
ellipsisLists.add(ellipsis);
} else {
int len = item.length();
float[] widths = new float[len];
mPaint.getTextWidths(item, 0, item.length(), widths);
if (mEllipsize == TextUtils.TruncateAt.END) {
float blockWidth = 0f;
for (int i = 0; i < len; i++) {
blockWidth += widths[i];
if (blockWidth > remaining) {
ellipsisLists.add(item.substring(0, i) + ellipsis);
break;
}
}
} else if (mEllipsize == TextUtils.TruncateAt.START) {
float blockWidth = 0f;
for (int i = len - 1; i >= 0; i--) {
blockWidth += widths[i];
if (blockWidth > remaining) {
ellipsisLists.add(ellipsis + item.substring(i, len - 1));
break;
}
}
} else if (mEllipsize == TextUtils.TruncateAt.MIDDLE) {
float blockWidth = 0f;
for (int i = 0, j = len - 1; i < j; i++, j--) {
blockWidth += (widths[i] + widths[j]);
if (blockWidth > remaining) {
if (blockWidth - widths[j] < remaining) {
ellipsisLists.add(item.substring(0, i + 1) + ellipsis + item.substring(j, len - 1));
} else {
ellipsisLists.add(item.substring(0, i) + ellipsis + item.substring(j, len - 1));
}
break;
}
}
}
}
}
}
}
lists = ellipsisLists;
}generateEllipsisText()方法用来对文字内容进行处理，当文字超过View长度时，多余的部分用省略号“...”代替。ellipsisLists就是用来存储处理后的文字的。avail表示可以显示文字的区域宽度，remaining是去除省略号“...”的宽度后，可以显示文字内容的宽度。使用Paint的measureText()方法可以获得字符串的宽度，这个宽度是对应于某一种字体和字号的，字体和字号不同，获得的宽度也就不同。Paint的getTextWidths()方法可以获得一个数组，数组中存储的是每一个字符的宽度。然后根据当前的ellipsize，通过计算字符长度与View宽度的关系，来确定最终要显示的文字内容。
//计算绘制的文字中心位置
switch (alignment) {
case TEXT_ALIGN_CENTER:
inTextCenterX = outTextCenterX = (mWidth - paddingLeft - paddingRight) / 2 + paddingLeft;
break;
case TEXT_ALIGN_LEFT:
inTextCenterX = paddingLeft + mPaint.measureText(inStr) / 2;
outTextCenterX = paddingLeft + mPaint.measureText(outStr) / 2;
break;
case TEXT_ALIGN_RIGHT:
inTextCenterX = mWidth - paddingRight - mPaint.measureText(inStr) / 2;
outTextCenterX = mWidth - paddingRight - mPaint.measureText(outStr) / 2;
break;
}上面的代码根据当前的gravity来计算文字绘制的x轴的中心位置，注意由于每项文字的长度不同，他们x轴的中心位置也不相同。
效果图如下
带有gravity属性和ellipsis属性的效果：
普通效果：
实例：
attrs.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="VerticalSwitchTextView">
<attr name="switchDuaration" format="integer"/>
<attr name="idleDuaration" format="integer"/>
<attr name="switchOrientation">
<enum name="up" value="0"/>
<enum name="down" value="1"/>
</attr>
<attr name="alignment">
<enum name="center" value="0"/>
<enum name="left" value="1"/>
<enum name="right" value="2"/>
</attr>
</declare-styleable>
</resources>string.xml
<resources>
<string name="app_name">VerticalSwitchTextView</string>
<string name="ellipsis">\u2026</string>
</resources>VerticalSwitchTextView.java
package com.viclee.verticalswitchtextview;
import android.animation.Animator;
import android.animation.ValueAnimator;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.View;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
public class VerticalSwitchTextView extends TextView implements View.OnClickListener {
private static final int DEFAULT_SWITCH_DURATION = 500;
private static final int DEFAULT_IDLE_DURATION = 2000;
public static final int TEXT_ALIGN_CENTER = 0;
public static final int TEXT_ALIGN_LEFT = 1;
public static final int TEXT_ALIGN_RIGHT = 2;
private Context mContext;
private List<String> lists;//会循环显示的文本内容
private List<String> ellipsisLists;
private int contentSize;
private String outStr;//当前滑出的文本内容
private String inStr;//当前滑入的文本内容
private float textBaseY;//文本显示的baseline
private int currentIndex = 0;//当前显示到第几个文本
private String ellipsis;
private float ellipsisLen = 0;
private int switchDuaration = DEFAULT_SWITCH_DURATION;//切换时间
private int idleDuaration = DEFAULT_IDLE_DURATION;//间隔时间
private int switchOrientation = 0;
private int alignment = TEXT_ALIGN_CENTER;
/**
* 文本中轴线X坐标
*/
private float inTextCenterX;
private float outTextCenterX;
private float currentAnimatedValue = 0.0f;
private ValueAnimator animator;
private TextUtils.TruncateAt mEllipsize;
private int verticalOffset = 0;
private int mWidth;
private int mHeight;
private int paddingLeft = 0;
private int paddingBottom = 0;
private int paddingTop = 0;
private int paddingRight = 0;
private Paint mPaint;
//回调接口，用来通知调用者控件当前的状态
public VerticalSwitchTextViewCbInterface cbInterface;
public VerticalSwitchTextView(Context context) {
this(context, null);
}
public VerticalSwitchTextView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public VerticalSwitchTextView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
mContext = context;
TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.VerticalSwitchTextView);
try {
switchDuaration = array.getInt(R.styleable.VerticalSwitchTextView_switchDuaration, DEFAULT_SWITCH_DURATION);
idleDuaration = array.getInt(R.styleable.VerticalSwitchTextView_idleDuaration, DEFAULT_IDLE_DURATION);
switchOrientation = array.getInt(R.styleable.VerticalSwitchTextView_switchOrientation, 0);
alignment = array.getInt(R.styleable.VerticalSwitchTextView_alignment, TEXT_ALIGN_CENTER);
} finally {
array.recycle();
}
init();
}
private void init() {
setOnClickListener(this);
mPaint = getPaint();
mPaint.setTextAlign(Paint.Align.CENTER);
ellipsis = getContext().getString(R.string.ellipsis);
ellipsisLen = mPaint.measureText(ellipsis);
mEllipsize = getEllipsize();
animator = ValueAnimator.ofFloat(0f, 1f).setDuration(switchDuaration);
animator.setStartDelay(idleDuaration);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
currentAnimatedValue = (float) animation.getAnimatedValue();
if (currentAnimatedValue < 1.0f) {
invalidate();
}
}
});
animator.addListener(new Animator.AnimatorListener() {
@Override
public void onAnimationStart(Animator animation) {
}
@Override
public void onAnimationEnd(Animator animation) {
currentIndex = (++currentIndex) % contentSize;
if (cbInterface != null) {
cbInterface.showNext(currentIndex);
}
outStr = lists.get(currentIndex);
inStr = lists.get((currentIndex + 1) % contentSize);
animator.setStartDelay(idleDuaration);
animator.start();
}
@Override
public void onAnimationCancel(Animator animation) {
}
@Override
public void onAnimationRepeat(Animator animation) {
}
});
}
/**
* 设置循环显示的文本内容
*
* @param content 内容list
*/
public void setTextContent(List<String> content) {
lists = content;
// lists.clear();
// lists = new ArrayList<>();
// lists.add("1适当放松放松放松点水电费水电费史蒂夫水电费水电费");
// lists.add("2适当放松放松放松点水电费水电费史蒂夫水电费水电费");
// lists.add("3适当放松放");
// lists.add("3适当放松放1111222333");
if (lists == null || lists.size() == 0) {
return;
}
contentSize = lists.size();
if (contentSize > 0) {
animator.start();
}
}
private void generateEllipsisText() {
if (ellipsisLists != null) {//防止重复计算
return;
}
ellipsisLists = new ArrayList<>();
if (lists != null && lists.size() != 0) {
for (String item : lists) {
int avail = mWidth - paddingLeft - paddingRight;
float remaining = avail - ellipsisLen;
if (avail <= 0) {
ellipsisLists.add("");
} else {
float itemWidth = mPaint.measureText(item, 0, item.length());
if (itemWidth < avail) {
ellipsisLists.add(item);
} else if (remaining <= 0) {
ellipsisLists.add(ellipsis);
} else {
int len = item.length();
float[] widths = new float[len];
mPaint.getTextWidths(item, 0, item.length(), widths);
if (mEllipsize == TextUtils.TruncateAt.END) {
float blockWidth = 0f;
for (int i = 0; i < len; i++) {
blockWidth += widths[i];
if (blockWidth > remaining) {
ellipsisLists.add(item.substring(0, i) + ellipsis);
break;
}
}
} else if (mEllipsize == TextUtils.TruncateAt.START) {
float blockWidth = 0f;
for (int i = len - 1; i >= 0; i--) {
blockWidth += widths[i];
if (blockWidth > remaining) {
ellipsisLists.add(ellipsis + item.substring(i, len - 1));
break;
}
}
} else if (mEllipsize == TextUtils.TruncateAt.MIDDLE) {
float blockWidth = 0f;
for (int i = 0, j = len - 1; i < j; i++, j--) {
blockWidth += (widths[i] + widths[j]);
if (blockWidth > remaining) {
if (blockWidth - widths[j] < remaining) {
ellipsisLists.add(item.substring(0, i + 1) + ellipsis + item.substring(j, len - 1));
} else {
ellipsisLists.add(item.substring(0, i) + ellipsis + item.substring(j, len - 1));
}
break;
}
}
}
}
}
}
}
lists = ellipsisLists;
}
/**
* 主要用来调整TextView的高度
*
* @param widthMeasureSpec
* @param heightMeasureSpec
*/
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
mWidth = MeasureSpec.getSize(widthMeasureSpec);
Rect bounds = new Rect();
if (contentSize <= 0) {
return;
}
String text = lists.get(0);
mPaint.getTextBounds(text, 0, text.length(), bounds);
int textHeight = bounds.height();
paddingLeft = getPaddingLeft();
paddingRight = getPaddingRight();
paddingBottom = getPaddingBottom();
paddingTop = getPaddingTop();
if (mEllipsize != null) {
generateEllipsisText();
}
outStr = lists.get(0);
if (contentSize > 1) {
inStr = lists.get(1);
} else {
inStr = lists.get(0);
}
mHeight = textHeight + paddingBottom + paddingTop;
Paint.FontMetrics fontMetrics = mPaint.getFontMetrics();
//计算文字高度
float fontHeight = fontMetrics.bottom - fontMetrics.top;
//计算文字的baseline
textBaseY = mHeight - (mHeight - fontHeight) / 2 - fontMetrics.bottom;
setMeasuredDimension(mWidth, mHeight);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (contentSize <= 0) {
return;
}
//计算绘制的文字中心位置
switch (alignment) {
case TEXT_ALIGN_CENTER:
inTextCenterX = outTextCenterX = (mWidth - paddingLeft - paddingRight) / 2 + paddingLeft;
break;
case TEXT_ALIGN_LEFT:
inTextCenterX = paddingLeft + mPaint.measureText(inStr) / 2;
outTextCenterX = paddingLeft + mPaint.measureText(outStr) / 2;
break;
case TEXT_ALIGN_RIGHT:
inTextCenterX = mWidth - paddingRight - mPaint.measureText(inStr) / 2;
outTextCenterX = mWidth - paddingRight - mPaint.measureText(outStr) / 2;
break;
}
//直接使用mHeight控制文本绘制，会因为text的baseline的问题不能居中显示
verticalOffset = Math.round(2 * textBaseY * (0.5f - currentAnimatedValue));
// L.d("verticalOffset is " + verticalOffset);
if (switchOrientation == 0) {//向上滚动切换
if (verticalOffset > 0) {
canvas.drawText(outStr, outTextCenterX, verticalOffset, mPaint);
} else {
canvas.drawText(inStr, inTextCenterX, 2 * textBaseY + verticalOffset, mPaint);
}
} else {
if (verticalOffset > 0) {//向下滚动切换
canvas.drawText(outStr, outTextCenterX, 2 * textBaseY - verticalOffset, mPaint);
} else {
canvas.drawText(inStr, inTextCenterX, -verticalOffset, mPaint);
}
}
}
@Override
public void onClick(View v) {
if (contentSize > currentIndex) {
if (cbInterface != null) {
cbInterface.onItemClick(currentIndex);
}
}
}
@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
mContext = null;
if (animator != null) {
animator.cancel();
}
}
//回调接口，用来通知调用者控件当前的状态,index表示开始显示哪一个文本内容
public interface VerticalSwitchTextViewCbInterface {
void showNext(int index);
void onItemClick(int index);
}
public void setCbInterface(VerticalSwitchTextViewCbInterface cb) {
cbInterface = cb;
}
}activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:vswitch="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<com.viclee.verticalswitchtextview.VerticalSwitchTextView
android:id="@+id/vertical_switch_textview1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:textColor="#aa0090"
android:textSize="30sp"
android:padding="8dp"
android:background="#999999"
android:ellipsize="end"
vswitch:alignment="left"
vswitch:switchDuaration = "500"
vswitch:idleDuaration = "1500"
vswitch:switchOrientation="up"/>
<com.viclee.verticalswitchtextview.VerticalSwitchTextView
android:id="@+id/vertical_switch_textview2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:layout_centerInParent="true"
android:textColor="#aa0090"
android:textSize="30sp"
android:padding="8dp"
android:background="#999999"
android:ellipsize="start"
vswitch:alignment="center"
vswitch:switchDuaration = "800"
vswitch:idleDuaration = "1000"
vswitch:switchOrientation="down"/>
</LinearLayout>MainActivity.java
package com.viclee.verticalswitchtextview;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.WindowManager;
import java.util.ArrayList;
import java.util.Arrays;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main);
ArrayList<String> list = new ArrayList<String>(Arrays.asList("能够适应多行长文本的Android TextView的例子", "理解的也很简单，我只是列出这个库里面我用到的一些方法",
"适当放松放", "密钥", "实现了两种方式来检测Android app前后台切换的状态", "科比"));
VerticalSwitchTextView verticalSwitchTextView1 = (VerticalSwitchTextView) findViewById(R.id.vertical_switch_textview1);
VerticalSwitchTextView verticalSwitchTextView2 = (VerticalSwitchTextView) findViewById(R.id.vertical_switch_textview2);
verticalSwitchTextView1.setCbInterface(new VerticalSwitchTextView.VerticalSwitchTextViewCbInterface() {
@Override
public void showNext(int index) {
}
@Override
public void onItemClick(int index) {
Log.e("aaaaaaaaa", "点击了" + index);
}
});
verticalSwitchTextView2.setCbInterface(new VerticalSwitchTextView.VerticalSwitchTextViewCbInterface() {
@Override
public void showNext(int index) {
}
@Override
public void onItemClick(int index) {
Log.e("aaaaaaaaa", "点击了" + index);
}
});
verticalSwitchTextView1.setTextContent(list);
verticalSwitchTextView2.setTextContent(list);
}
}完！！！
注：此方法会频繁更新绘制，容易造成页面卡顿！！！
可以考虑使用TextSwitcher控件，参考下一篇
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