安卓多点触控？

Question

作为一名开发人员，我倾向于先编程，然后再研究。我试图实现一个可以处理多个用户输入的屏幕。基本上映射的不仅仅是一根手指。我尝试了两件事......

我有一个实现 OnTouchListener 的 Activity 类。这里我有两个单独的子视图，它们将 Activity 添加为它们的 ontouch 监听器。然后我有一个打印行，打印出 event.getPointerCount() 并打印出每个指针的位置。

将其下载到手机并进行测试。我注意到指针永远不会超过两个。我什至注意到，如果一根手指放在一个子视图上，另一根手指放在另一个子视图上，则事件只会到达第一个子组件。接下来，我尝试在每个子组件上放置单独的侦听器，看看这是否有效，但其行为相同。

因此，在处理用户触摸屏幕的输入时，Android 似乎只支持总共两个用户输入。

这是真的吗？从测试和研究来看，情况确实如此。

有没有人遇到过这个限制。有什么巧妙的解决方法吗？

感谢您的时间和回复。

dk

Answer 1

支持的触摸点数量取决于设备。在所有当前可用的 Android 版本中，MotionEvent 都会发送到单个目标视图并描述所有当前活动触摸点的状态。目标视图由第一个 MotionEvent.ACTION_DOWN 事件发生的位置确定。

请参阅帖子 了解多点触控 Android 开发人员博客，快速概述如何在 Android 上处理多点触控事件。

Answer 2

我编写了一个非常简单的应用程序来测试我的 HTC Incredible 手机上的多点触摸。我的行为与我的想法非常相似，并且与 adamp 给出的 URL 非常相似。我的结果是手机只能处理两个手指输入。我有一个盒子，每个盒子都有自己的 OnTouchListener。当我单击每个框时，我会打印每个框的文本。单击每个获取触摸事件，但用食指单击屏幕上的任意位置，我得到两个指针。来自 MotionEvent event.getPointerCount 方法。第二根手指落在哪里并不重要。可能位于接收第一个手指按下事件的原始视图之外。无论如何，如果您想自己尝试一下，这里是代码。

我有整个项目的 7z，但我认为我无法附加它。

所以，这里是主要的 Activity 和布局的 xml。

package com.multitouch;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.LinearLayout;
import android.widget.TextView;

public class MultiTouch extends Activity {
    protected LinearLayout sq1;
    protected LinearLayout sq2;
    protected LinearLayout sq3;
    protected LinearLayout sq4;

    protected String sqText = new String();
    protected String sq1Text = new String();
    protected String sq2Text = new String();
    protected String sq3Text = new String();

    private Handler handler = new Handler();

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        setViews();
        handler.postDelayed(mUpdateUITimerTask, 5000);
    }

    private final Runnable mUpdateUITimerTask = new Runnable() {
        public void run() {
            // do whatever you want to change here, like:
            updateTextField();
        }
    };

    private void updateTextField() {
        TextView view1 = (TextView) this.findViewById(R.id.logView);
        TextView view2 = (TextView) this.findViewById(R.id.logView1);
        TextView view3 = (TextView) this.findViewById(R.id.logView2);
        TextView view4 = (TextView) this.findViewById(R.id.logView3);


        //view1.append(sqText + "\n");
        view1.setText(sqText);
        view2.setText(sq1Text);
        view3.setText(sq2Text);
        view4.setText(sq3Text);

        handler.post(mUpdateUITimerTask);
    }

    private void setViews() {
         sq1 = (LinearLayout) this.findViewById(R.id.square1);
         sq2 = (LinearLayout) this.findViewById(R.id.square2);
         sq3 = (LinearLayout) this.findViewById(R.id.square3);
         sq4 = (LinearLayout) this.findViewById(R.id.square4);

         sq1.setOnTouchListener(new TouchListener());
         sq2.setOnTouchListener(new TouchListener());
         sq3.setOnTouchListener(new TouchListener());
         sq4.setOnTouchListener(new TouchListener());        
    }

    private class TouchListener implements OnTouchListener {

        @Override
        public boolean onTouch(View v, MotionEvent event) {

             if(event.getPointerCount()>2) {
                sq1Text = "GOT THREE POINTERS!!";
                sq2Text = "GOT THREE POINTERS!!";
                sq3Text = "GOT THREE POINTERS!!";
                sqText = "GOT THREE POINTERS!!";
             }

             if(event.getAction() == MotionEvent.ACTION_DOWN){
                switch(v.getId()) {
                   case R.id.square1:
                       sqText = "Square 1 Pressed::Pointer count = " + String.valueOf(event.getPointerCount()); 
                   break;
                   case R.id.square2:
                       sq1Text = "Square 2 Pressed::Pointer count = " + String.valueOf(event.getPointerCount()); 
                   break;
                   case R.id.square3:
                       sq2Text = "Square 3 Pressed::Pointer count = " + String.valueOf(event.getPointerCount()); 
                   break;
                   case R.id.square4:
                       sq3Text =  "Square 4 Pressed::Pointer count = " + String.valueOf(event.getPointerCount()); 
                   break;
                }
             }  else if(event.getAction() == MotionEvent.ACTION_POINTER_DOWN ||
                        event.getAction() == MotionEvent.ACTION_POINTER_UP) {
                 switch(v.getId()) {
                   case R.id.square1:
                       sqText = "Square 1 Pointer Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square2:
                       sq1Text =  "Square 2 Pointer Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square3:
                       sq2Text =  "Square 3 Pointer Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square4:
                       sq3Text =  "Square 4 Pointer Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                }
             } else if(event.getAction() == MotionEvent.ACTION_POINTER_1_DOWN) {
                 switch(v.getId()) {
                   case R.id.square1:
                       sqText = "Square 1 Pointer1Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square2:
                       sq1Text =  "Square 2 Pointer1Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square3:
                       sq2Text =  "Square 3 Pointer1Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square4:
                       sq3Text = "Square 4 Pointer1Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                }
             } else if(event.getAction() == MotionEvent.ACTION_POINTER_2_DOWN) {
                 switch(v.getId()) {
                   case R.id.square1:
                       sqText = "Square 1 Pointer2Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square2:
                       sq1Text =  "Square 2 Pointer2Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square3:
                       sq2Text =  "Square 3 Pointer2Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square4:
                       sq3Text =  "Square 4 Pointer2Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                }
             } else if(event.getAction() == MotionEvent.ACTION_POINTER_3_DOWN) {
                 switch(v.getId()) {
                   case R.id.square1:
                       sqText =  "Square 1 Pointer3Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square2:
                       sq1Text =  "Square 2 Pointer3Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square3:
                       sq2Text =  "Square 3 Pointer3Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square4:
                       sq3Text = "Square 4 Pointer3Down::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                }
             } else if(event.getAction() == MotionEvent.ACTION_UP) {
                 switch(v.getId()) {
                   case R.id.square1:
                       sqText = "Square 1 UP::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square2:
                       sq1Text =  "Square 2 UP::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square3:
                       sq2Text =  "Square 3 UP::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square4:
                       sq3Text =  "Square 4 UP::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                }
             } else if(event.getAction() == MotionEvent.ACTION_MOVE) {
                 switch(v.getId()) {
                   case R.id.square1:
                       sqText = "Square 1 MOVE::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square2:
                       sq1Text =  "Square 2 MOVE::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square3:
                       sq2Text =  "Square 3 MOVE::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                   case R.id.square4:
                       sq3Text =  "Square 4 MOVE::Pointer count = " + String.valueOf(event.getPointerCount()) + "\n"; 
                   break;
                }
             }


            // TODO Auto-generated method stub
            return true;
        }

    }
}

布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:gravity="center_horizontal"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:id="@+id/MainLay" >

    <TableLayout xmlns:android="http://schemas.android.com/apk/res/android"  
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical"
        android:gravity="center_horizontal" android:padding="10dip">


        <TableRow android:gravity="center_horizontal" android:padding="10dip">
            <LinearLayout android:background="#FFFF00" android:id="@+id/square1" android:padding="10px" android:layout_width="125px" android:layout_height="125px"/>
            <LinearLayout android:background="#FF00FF" android:id="@+id/square2" android:padding="10px" android:layout_width="125px" android:layout_height="125px"/>
        </TableRow>

        <TableRow android:gravity="center_horizontal" android:padding="10dip">
            <LinearLayout android:background="#00FFFF" android:id="@+id/square3" android:padding="10px" android:layout_width="125px" android:layout_height="125px"/>
            <LinearLayout android:background="#eeeeee" android:id="@+id/square4" android:padding="10px" android:layout_width="125px" android:layout_height="125px"/>
        </TableRow>     


          <TextView android:id="@+id/logView" android:layout_width="wrap_content" android:layout_height="wrap_content"/>
          <TextView android:id="@+id/logView1" android:layout_width="wrap_content" android:layout_height="wrap_content"/>
          <TextView android:id="@+id/logView2" android:layout_width="wrap_content" android:layout_height="wrap_content"/>
          <TextView android:id="@+id/logView3" android:layout_width="wrap_content" android:layout_height="wrap_content"/>



    </TableLayout>

</LinearLayout>

祝你好运，如果你尝试一下，请告诉我你是否得到了三个指针！打印报表。我想知道什么手机支持它。

谢谢，
dk

Answer 3

我编辑了@dakira 答案。这是我的示例代码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/MainLay"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:gravity="center_horizontal"
    android:orientation="vertical">


    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:id="@+id/tvHeader"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:padding="4dp"
            android:text="Place Your Finger on Squire"
            android:textColor="#000"
            android:textSize="20sp" />

        <LinearLayout
            android:id="@+id/llStatusHolder"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/tvHeader"
            android:orientation="vertical"
            android:weightSum="2">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:padding="8dp"
                android:weightSum="2">

                <TextView
                    android:id="@+id/tvBox1"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:background="#FFFF00"
                    android:gravity="center"
                    android:padding="4dp"
                    android:text="Finger : 0"
                    android:textColor="#000"
                    android:textSize="28sp" />

            </LinearLayout>

        </LinearLayout>


        <LinearLayout
            android:id="@+id/square1"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_margin="4dp"
            android:layout_below="@+id/llStatusHolder"
            android:layout_weight="1"
            android:background="#FFFF00"
            android:orientation="horizontal"
            android:padding="10dp">

        </LinearLayout>

        </RelativeLayout>
    </LinearLayout>

这是 JAVA 代码：

import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.LinearLayout;
import android.widget.TextView;


public class MultiTouchTestActivity extends Activity {
    protected LinearLayout sq1;

    TextView tvBox1;
    int counter1 = 0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_multi_touch_test);
        setViews();
    }

    private void updateTextField() {

        tvBox1.setText("Finger : " + counter1);

    }

    private void setViews() {
        tvBox1 = (TextView) findViewById(R.id.tvBox1);
        sq1 = (LinearLayout) this.findViewById(R.id.square1);

        sq1.setOnTouchListener(new TouchListener());

    }

    private class TouchListener implements OnTouchListener {

        @Override
        public boolean onTouch(View v, MotionEvent event) {

            if (event.getAction() == 1) {
                setCounterValue(1, 0);
            }else if (event.getAction() == MotionEvent.ACTION_DOWN) {
                setCounterValue(1, event.getPointerCount());
            } else if (event.getAction() == MotionEvent.ACTION_POINTER_DOWN ||
                    event.getAction() == MotionEvent.ACTION_POINTER_UP) {
                setCounterValue(1, event.getPointerCount());
            } else if (event.getAction() == MotionEvent.ACTION_POINTER_1_DOWN) {
                setCounterValue(1, event.getPointerCount());
            } else if (event.getAction() == MotionEvent.ACTION_POINTER_2_DOWN) {
                setCounterValue(1, event.getPointerCount());
            } else if (event.getAction() == MotionEvent.ACTION_POINTER_3_DOWN) {
                setCounterValue(1, event.getPointerCount());
            } else if (event.getAction() == MotionEvent.ACTION_UP) {
                setCounterValue(1, event.getPointerCount());
            } else if (event.getAction() == MotionEvent.ACTION_MOVE) {
                setCounterValue(1, event.getPointerCount());
            }else if (event.getAction() == MotionEvent.ACTION_BUTTON_RELEASE) {
                setCounterValue(1, 0);
            }
            updateTextField();
            return true;
        }
    }

    void setCounterValue(int hasvalue, int value) {
        switch (hasvalue) {
            case 1:
                counter1 = value;
                break;
        }
    }
}

希望这能解决很多人的问题:)