Button android 图片大小 android图片按钮

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mob6454cc74c0fc 2023-09-19 16:20:18

文章标签 android exception null constructor class 文章分类 Android 移动开发

学习android两个多月了，开始时连java都没搞懂是啥玩意，幸好有些c，c++基础。然后每天看博客，逛论坛。渐渐的对java的语法，应用等方面有了些了解。一直以来，看到像qq，新浪微博等软件，特别是游戏的界面，都非常神往。想和某一天也可以开发个应用程序能够拥有如此绚丽的界面。

心理有些冲动了，果断在当当上买了一本《android2.0游戏看法实战宝典》，开始了学习之路。

一般来说，实现用户的交互，按钮是很常用的控件，android自带的按钮太经典了，有点确认个人色彩。因此我自己动手些了个ImageButton的类，方便以后的使用。ImageButton这个类要实现的方法主要有一下几点：1.检测触摸屏按下的位置是否为按钮所在的区域；2.点击按钮的时候反馈信息给用户，我这里为了简单起见，主要给按钮加了个边框而已；3.最重要的，当然是实现相应事件了。

一下是基于canvas应用的ImageButton类的代码：

package lxx.mygame;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Paint.Style;
import android.util.Log;


public class ImageButton {
 Bitmap bitmap;
 Rect rect;
 int x; 
 int y;
 boolean isTouch = false;
 
 
  ImageButton(Bitmap bitmap, int x, int y){
 this.bitmap = bitmap;//得到图片资源
 this.x = x;
 this.y = y;
 rect = new Rect(x,y,x+bitmap.getWidth(),y+bitmap.getHeight());//记录位图的矩形区域
  } 
 
  public void drawImage(Canvas canvas){//界面上显示ImageButton
 canvas.drawBitmap(bitmap, x, y, null);
 
 if(isTouch ){//检测触摸点是否在按钮区域，然后决定是否加边框
  Paint borderPaint = new Paint();
  borderPaint.setStyle(Style.STROKE);
  borderPaint.setARGB(255, 255, 0, 0);
  borderPaint.setStrokeWidth(4f);
  canvas.drawRect(rect, borderPaint);    
 }
   
  }

  public boolean getClicked(int x, int y){){//检测触摸点是否在按钮区域
  boolean ret = false;
  if(rect.contains(x,y))
  {
  ret = true; 
  isTouch = true;
  }
  
  return ret; 
  }
  
  public void getButtonUp(){//检测触摸屏的释放
   
   isTouch = false;
  }
  
  public void dragButton(int x, int y){//拖动按钮
   if(isTouch){   
  this.x = x;//保存新的坐标
     this.y = y; 
     int width = bitmap.getWidth();
     int height = bitmap.getHeight();
     rect = new Rect(x,y,x+width,y+height);  
  Log.d("Season","x:" + x + " y:"+y) ; 
   }
   
  }
  
  
 
}

Activity中的代码如下：

package lxx.mygame;

import android.app.Activity;
import android.content.pm.ActivityInfo;
import android.os.Bundle;
import android.view.Window;
import android.view.WindowManager;


public class MygameActivity extends Activity {
    /** Called when the activity is first created. */
 WelcomView welcomView;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        requestWindowFeature(Window.FEATURE_NO_TITLE);//去掉标题
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
                       WindowManager.LayoutParams.FLAG_FULLSCREEN);//全屏显示
        
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);//横屏显示
        welcomView = new WelcomView(this);
        setContentView(welcomView);   
    }
     
  
}

WelcomView 类主要实现触摸屏位置的检测，然后对按钮进行相应的处理

package lxx.mygame;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.widget.Toast;

public class WelcomView extends SurfaceView implements SurfaceHolder.Callback{
 
 MygameActivity father;
 WelcomThread welcomThread;
 Bitmap background;
 Bitmap startBitmap;
 Bitmap clubBitmap;
 Bitmap speedBitmap;
 ImageButton start;
 ImageButton club;
 boolean speedEnable = false;
 int x;
 int y;

 public WelcomView(MygameActivity father) {
  super(father);
  // TODO Auto-generated constructor stub
  this.father = father;
  getHolder().addCallback(this);
  initBitmap(father);
  start = new ImageButton(startBitmap,40,40);
  club = new ImageButton(clubBitmap,100,40);
  
 }

 public void doDraw(Canvas canvas){
  Paint paint = new Paint();
  paint.setColor(Color.BLACK);
  
  canvas.drawColor(Color.BLACK);
  canvas.drawBitmap(background, 0,0, null);
  
  start.drawImage(canvas);
  club.drawImage(canvas);
  
  
 }

@Override
 public boolean onTouchEvent(MotionEvent event) {
  // TODO Auto-generated method stub
  int x = (int) event.getX();
  int y = (int) event.getY();
  
  switch(event.getAction())
  {
   case MotionEvent.ACTION_DOWN://按下按钮
    if(start.getClicked(x, y)){
     Toast.makeText(getContext(), "你点击了开始按钮", Toast.LENGTH_SHORT).show();   
    }
   
    if(club.getClicked(x, y)){
     Toast.makeText(getContext(), "你点击了club按钮", Toast.LENGTH_SHORT).show();
    }
      
          
         this.x = x;
      this.y= y;        
         break;
    
   case MotionEvent.ACTION_UP://释放按钮
     start.getButtonUp();
     club.getButtonUp();
     speedEnable =false;
      this.x = x;
      this.y= y;
        break;
        
   case MotionEvent.ACTION_MOVE://拖动按钮
    start.dragButton(x, y);
    club.dragButton(x, y);   
   
    
      this.x = x;
      this.y= y;
        break;     
        
  }
  
  
  
  return true;
 }

 
 
 public void initBitmap(Context context){//初始化图片资源
  Resources r = context.getResources();
  background = BitmapFactory.decodeResource(r, R.drawable.welcome);
  startBitmap = BitmapFactory.decodeResource(r, R.drawable.start);
  clubBitmap = BitmapFactory.decodeResource(r, R.drawable.club);
   
 }
 
 
 
 @Override
 public void surfaceChanged(SurfaceHolder holder, int format, int width,
   int height) {
  // TODO Auto-generated method stub
  
 }

 @Override
 public void surfaceCreated(SurfaceHolder holder) {
  // TODO Auto-generated method stub
  welcomThread = new WelcomThread(this,getHolder());
  this.welcomThread.flag = true;
  welcomThread.start();
   
 }

 @Override
 public void surfaceDestroyed(SurfaceHolder holder) {
  // TODO Auto-generated method stub
  boolean retry =true;
  welcomThread.flag = false;
  while(retry){
   try{
     welcomThread.join();//等待线程的结束
        retry = false;
    }
   catch(InterruptedException e){
    
    e.printStackTrace();
   }
  }
   
 }
 
  
}

在WelcomThread中主要定时的刷新界面

package lxx.mygame;

import android.graphics.Canvas;
import android.util.Log;
import android.view.SurfaceHolder;

public class WelcomThread extends Thread{
    int sleepSpan = 50;
    WelcomView father;
    SurfaceHolder surfaceHolder;
    boolean flag ;
    
    WelcomThread(WelcomView father, SurfaceHolder surfaceHolder){
     this.father = father;
     this.surfaceHolder = surfaceHolder;
     this.flag = true;
    }
    
 @Override
 public void run() {
  // TODO Auto-generated method stub
   Canvas canvas = null;
   while(flag){
    try{
     canvas = surfaceHolder.lockCanvas(null);//锁住画布
     synchronized(surfaceHolder){
      father.doDraw(canvas);
           
     }
    }
    
    catch(Exception e)
    {
   e.printStackTrace();      
    }
    
    finally{
     if(canvas != null)
     {
    surfaceHolder.unlockCanvasAndPost(canvas);  //显示新的画布
     }   
    }
    
    
    try{
     Thread.sleep(sleepSpan);  //休眠一小会
    }
    
    catch (Exception e)
    {
   e.printStackTrace();  
     
    }
    
    
 }
 
}
 
 
}

最后的显示效果如下图，可以任意拖动按钮并触发事件等，因为比较细化极品飞车，就把他弄了个背景，哈哈

Button android 图片大小 android图片按钮_class