[Android] 高速实现一个通用EmptyView

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mb5fd340813ba80 2017-05-25 12:25:00

文章标签 android ide xml 布局文件网络连接 文章分类 代码人生

好的APP应当具备良好的交互, 最好能贴心的满足用户的需求. 而人性化的提醒就是当中之中的一个. 某些APP中常常会看到这种场景, 当载入内容失败, 或者获取内容失败时, 界面会变成一个可与用后交互的场景. 同意用户点击屏幕或者界面中某个button, 尝试又一次获取内容或者检測网络连接等等. Android的ListView中有类似setEmptyView(...) 的方法, 当列表中没有数据, 就会显示该 emptyView. 但并不是全部的View都有这种接口方法, 为此我们能够自己去实现可通用的"emptyView".

这里通过简单的样例提供一种思路, 当然不是唯一的. 我们能够依据自己的想法实现各种各样的emptyView本质还是调用view.setVisibility(...).

效果图例如以下, 看起来好简单吧!

[Android] 高速实现一个通用EmptyView_android

So 直接上代码喇!

将EmptyView封装在某个经常使用布局文件里, 比方RelativeLayout, 当然也能够是LinearLayout等等.

public class CustomRelativeLayout extends RelativeLayout{
    public static interface RetryListener{
        void retry();
    }

    private ProgressBar progressBar = null;
    private Button btn_refresh = null;
    private TextView tv_tip = null;
    private boolean isNormal = true;
    private RetryListener retryListener = null;

    private final static int tvTipId = 0x1001;


    public CustomRelativeLayout(Context context) {
        this(context, null);
    }


    public CustomRelativeLayout(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public CustomRelativeLayout(Context context, AttributeSet attrs,
                                int defStyle) {
        super(context, attrs, defStyle);
    }


    /**
     * 设置载入界面
     */
    protected void setInProgress()
    {
        if(progressBar == null)
        {
            int size = (int) TypedValue
                    .applyDimension(TypedValue.COMPLEX_UNIT_DIP, 45, getResources().getDisplayMetrics());
            progressBar = new ProgressBar(getContext());
            RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(size,size);
            lp.addRule(RelativeLayout.CENTER_IN_PARENT);
            progressBar.setLayoutParams(lp);
            addView(progressBar);
        }

        if(getChildCount() > 0)
        {
            int childCount = getChildCount();
            if(childCount >0)
            {
                for(int i=(childCount-1); i>=0; i--)
                {
                    getChildAt(i).setVisibility(View.GONE);
                }
            }
        }

        if(btn_refresh != null)
            btn_refresh.setVisibility(View.GONE);
        if(tv_tip != null)
            tv_tip.setVisibility(View.GONE);

        progressBar.setVisibility(View.VISIBLE);
    }

    /**
     * 显示载入失败界面,隐藏全部正常的View元素
     */
    protected void setChildrenGone()
    {
        if(btn_refresh == null)
        {
            btn_refresh = new Button(getContext());
            tv_tip = new TextView(getContext());
            tv_tip.setText("网络连接失败");
            tv_tip.setGravity(Gravity.CENTER);
            tv_tip.setTextSize(TypedValue.COMPLEX_UNIT_SP, 16);
            btn_refresh.setText("刷新");

            btn_refresh.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(retryListener != null)
                    {
                        retryListener.retry();
                    }
                    else
                    {
                        Toast.makeText(getContext(), "暂无数据", Toast.LENGTH_SHORT).show();
                    }
                }
            });
            int btnWidth = (int)TypedValue
                    .applyDimension(TypedValue.COMPLEX_UNIT_DIP, 80, getResources().getDisplayMetrics());
            RelativeLayout.LayoutParams lp
                    = new RelativeLayout.LayoutParams(btnWidth, LayoutParams.WRAP_CONTENT);
            lp.addRule(RelativeLayout.CENTER_IN_PARENT);
            lp.setMargins(0, 10, 0, 0);
            btn_refresh.setLayoutParams(lp);
            btn_refresh.setId(tvTipId);
            btn_refresh.setVisibility(View.GONE);
            addView(btn_refresh);

            RelativeLayout.LayoutParams lp_tv
                    = new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
            lp_tv.addRule(RelativeLayout.ABOVE, tvTipId);
            tv_tip.setLayoutParams(lp_tv);
            addView(tv_tip);
        }

        if(getChildCount() > 0)
        {
            int childCount = getChildCount();
            if(childCount >0)
            {
                for(int i=(childCount-1); i>=0; i--)
                {
                    getChildAt(i).setVisibility(View.GONE);
                }
            }
        }

        if(progressBar != null)
            progressBar.setVisibility(View.GONE);

        isNormal = false;
        btn_refresh.setVisibility(View.VISIBLE);
        tv_tip.setVisibility(View.VISIBLE);
    }

    /**
     * 显示正常View元素
     */
    protected void setChildrenVisible()
    {
        if(getChildCount() > 0)
        {
            int childCount = getChildCount();
            if(childCount >0)
            {
                for(int i=(childCount-1); i>=0; i--)
                {
                    getChildAt(i).setVisibility(View.VISIBLE);
                }
            }
            if(progressBar != null)
                progressBar.setVisibility(View.GONE);

            if(btn_refresh != null)
                btn_refresh.setVisibility(View.GONE);

            if(tv_tip != null)
                tv_tip.setVisibility(View.GONE);

            isNormal = true;
        }
    }

    protected boolean isNormalView()
    {
        return isNormal;
    }

    public void setRetryListener(RetryListener listener)
    {
        this.retryListener = listener;
    }


}

提供一个RetryListener接口, 作为点击 "刷新" button后的事件.

然后模拟载入中而且载入失败的界面, 点击button后拖延3秒, 如果获取数据成功, 更新view后显示正常的界面.

public class MainActivity extends Activity {
    private Button btn_start = null;
    private static CustomRelativeLayout cuLayout = null;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        init();
    }


    private static Handler mHandler = new Handler()
    {
       @Override
        public void handleMessage(Message msg)
       {
           if(msg.what == 0x1)
           {
               cuLayout.setChildrenVisible();
           }
           else if(msg.what == 0x2)
           {
               cuLayout.setChildrenGone();
           }
           super.handleMessage(msg);
       }
    };

    private void init()
    {
        btn_start = (Button) findViewById(R.id.btn_start);
        cuLayout = (CustomRelativeLayout) findViewById(R.id.container);

        cuLayout.setRetryListener(new CustomRelativeLayout.RetryListener(){
            public void retry()
            {
                cuLayout.setInProgress();
                mHandler.sendEmptyMessageDelayed(0x1,3000);
            }
        });


        btn_start.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                cuLayout.setChildrenGone();
            }
        });

        cuLayout.setInProgress();
        mHandler.sendEmptyMessageDelayed(0x2,2000);
    }




}

布局文件:

<com.alextam.progressview.CustomRelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    >

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="#FFFFFF"
        >

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="250dp"
            android:src="@mipmap/movie"
            />

        <Button
            android:id="@+id/btn_start"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:text="ACTION"
            />

    </RelativeLayout>

</com.alextam.progressview.CustomRelativeLayout>