Android Touch(3)View的touchDelegate

作用：

基类View有个函数 public void setTouchDelegate(TouchDelegate delegate)，给view内部的另一个view设置一个touch代理。

图中view是外部view,它包含tv1,tv2两个内部view, view可以给tv1,tv2设置一个touch矩形区域(图中黄色rect1)，rect1以view的左上为原点，当手指在rect1产生touch事件时，会触发tv1,tv2的 touch事件，相当于给tv1,tv2增加了另一个touch区域rect1。tv2与rect1部分重合，产生两次回调onTouchListener。

注意：必需是外部的view给内部的tv1,tv2设置touchDelegate,见代码红色部分。

代码：

 import android.app.Activity;
 import android.graphics.Rect;
 import android.os.Bundle;
 import android.view.MotionEvent;
 import android.view.TouchDelegate;
 import android.view.View;
 import android.widget.TextView;

 public class MainActivity extends Activity {

     View rootLayout;
     TouchDelegate delegateTV1,delegateTV2;
     TextView tv1,tv2;

     void setTv1Deletegate(){
         tv1 = (TextView) findViewById(R.id.tv1);

         Rect delegateRect;
         delegateRect = new Rect(, , , );
         delegateTV1 = new TouchDelegate(delegateRect, tv1);

         rootLayout.setTouchDelegate(delegateTV1);

         tv1.setOnTouchListener(new View.OnTouchListener() {
             @Override
             public boolean onTouch(View v, MotionEvent event) {
                 System.out.println(String.format("tv1 touched ,x = %f, y = %f ", event.getX(),event.getY()));
                 return false;
             }
         });
     }
     void setTv2Deletegate(){
         tv2 = (TextView) findViewById(R.id.tv2);
         View touchRect = findViewById(R.id.touchRect);

         Rect delegateRect;

         delegateRect = new Rect(, -, , );//这个rect无效，因为它在touchRect范围之外。

         delegateTV2 = new TouchDelegate(delegateRect, tv2);

         touchRect.setTouchDelegate(delegateTV2);

         tv2.setOnTouchListener(new View.OnTouchListener() {
             @Override
             public boolean onTouch(View v, MotionEvent event) {
                 System.out.println(String.format("tv2 touched ,x = %f, y = %f ", event.getX(),event.getY()));
                 return false;
             }
         });
     }
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         rootLayout = findViewById(R.id.activity);

         setTv1Deletegate();

         setTv2Deletegate();
     }
 }

activity_main.xml

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/activity"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:gravity="center_horizontal"
     android:padding="10dp"
     tools:context="com.example.delegatetouch.MainActivity" >

     <TextView
         android:id="@+id/tv1"
         android:layout_width="match_parent"
         android:layout_height="100dp"
         android:background="#d8988e"
         android:gravity="center_horizontal|center_vertical"
         android:text="tv1" />

     <LinearLayout
         android:layout_width="400dp"
         android:layout_height="200dp"
         android:id="@+id/touchRect"
         android:background="#EEE685"
         android:layout_alignLeft="@+id/tv1"
         android:layout_alignParentBottom="true"
         android:orientation="vertical" >

         <TextView
             android:id="@+id/tv2"
             android:layout_width="200dp"
             android:layout_height="100dp"
             android:layout_marginLeft="22dp"
             android:background="#d8988e"
             android:gravity="center_horizontal|center_vertical"
             android:text="tv2" />

         <TextView
             android:id="@+id/touchtv"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:layout_gravity="center_horizontal"
             android:text="rect1" />

     </LinearLayout>

     <TextView
         android:id="@+id/view"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_above="@+id/touchRect"
         android:layout_centerHorizontal="true"
         android:layout_marginBottom="55dp"
         android:text="view" />

 </RelativeLayout>