我如何在android中正确处理触摸事件？

Question

项目范围

当用户用两根手指触摸 Android 屏幕时，在每个触摸位置绘制一个“框架”，每个框架都有一个“光标”。每个框架都是一个自定义滑块，光标将上下移动。一路向上为 100%，中间为 0%，一路向下为-100%。这将用于控制小型电机，类似于坦克转动，每次触摸控制一个单独的电机（通过蓝牙发送信号）。两次触摸并绘制所有内容后，我希望能够松开任一手指，但将光标保持在上次所在的位置，而另一根手指可以自由移动光标。当最后一根手指松开时，所有内容都会“隐藏”并重置为 0%。

所需功能

1. 在两根手指触摸时，在触摸位置下绘制单独的 .png
2. 绘制框架和光标后，跟踪它们相对于框架的位置以确定百分比。
3. 如果手指离开，则将该手指光标保持在最后已知的位置，但另一根手指可以移动其光标。此外，如果手指放回原处，它应该能够再次移动光标。
4. 如果双手指离开屏幕，隐藏所有内容并将百分比重置为 0%

获得功能

• 我可以在多点触控上绘制框架和光标 位置
• 和百分比工作正常
• 光标可以正确移动

什么不起作用

• 我不确定我是否应该有一个自定义类来处理两个触摸事件，或者我是否应该有两个自定义类实例，每个实例都处理自己的触摸事件（我已经尝试过这两种方法，这是我得到的唯一方法）任何“真实”功能是使用 1 个自定义类处理两个触摸事件，另一种方式无法按预期工作）
• 当我只有 1 个自定义类时，它效果很好，但如果两个手指不在屏幕上，我会“隐藏”所有内容，有时android会注册我已经将手指从屏幕上抬起，当框架隐藏然后重新出现在不同的位置时，这会导致很多问题当
• 我使用2个自定义类时，我触摸每个自定义类都会有自己的触摸事件，如果我的话，我就不必担心多点触控在屏幕之间均匀分配班级。事实并非如此，仍然需要处理多点触控

有人可以向我解释android如何处理他们的触摸事件。从我所做的来看，如果我放下手指1，手指2，第一个手指将注册一个“ACTION_DOWN”，第二个手指将注册一个“ACTION_POINTER_2_DOWN”，但是如果我靠第一个手指、第二个手指生活被“降级”，现在我的第二根手指注册的所有事件都与“ACTION_POINTER_2”无关，而是“ACTION_DOWN、ACTION_UP 等”。这是正确的吗？

TouchUI.java

    package com.robota.android;

    import android.content.Context;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.graphics.Canvas;
    import android.util.AttributeSet;
    import android.util.Log;
    import android.view.MotionEvent;
    import android.widget.ImageView;

public class TouchUI extends ImageView {

public static final String LEFT_TOUCHUI = "com.robota.android:id/leftTouchUI";
public static final String RIGHT_TOUCHUI = "com.robota.android:id/rightTouchUI";
private String whoAmI = new String();
private MyPoints framePts = new MyPoints();
private MyPoints cursorPts = new MyPoints();
private Bitmap frame;
private Bitmap cursor;
private int frameWidth;
private int frameHeight;
private int cursorHeight;
private boolean pointerDown = false;
private int dy;

public TouchUI(final Context context, final AttributeSet as){
    super(context, as);
    Log.d("TouchUI", getResources().getResourceName(this.getId()));
    whoAmI = new String(getResources().getResourceName(this.getId()));
    if(whoAmI.equals(LEFT_TOUCHUI)){
        frame = BitmapFactory.decodeResource(getResources(), R.drawable.tank_left);
    }else if(whoAmI.equals(RIGHT_TOUCHUI)){
        frame = BitmapFactory.decodeResource(getResources(), R.drawable.tank_right);
    }
    cursor = BitmapFactory.decodeResource(getResources(), R.drawable.cursor);
    frameWidth = frame.getWidth();
    frameHeight = frame.getHeight();
    cursorHeight = cursor.getHeight();
}

public void determinePointers(int x, int y){
        framePts.setOrigin(x-frameWidth/2, y-frameHeight/2);
        cursorPts.setOrigin(x-frameWidth/2, y-frameHeight/2);
}

@Override
public boolean onTouchEvent(MotionEvent e){
    int x = 0;
    int y = 0;
    Log.d("TouchUI", ">>>>> " + whoAmI);
    if(e.getAction() == MotionEvent.ACTION_DOWN){
        determinePointers(x,y);
        pointerDown = true;
    }else if(e.getAction() == MotionEvent.ACTION_UP){
        pointerDown = false;
    }else if(e.getAction() == MotionEvent.ACTION_MOVE){
        dy = (int)e.getY()-framePts.getY();
        if(dy <= 0){
            dy=0;
        }else if(dy+cursorHeight/2 >= frameHeight){
            dy=frameHeight;
        }
        sendMotorSpeed(dy);
    }
    return true;
}

public void sendMotorSpeed(int dy){
    float motor = dy;
    motor-=frameHeight;
    motor*=-1;

    motor = (motor/frameHeight)*255;

    PacketController.updateMotorSpeeds(whoAmI, (int)motor);
}

public void onDraw(Canvas canvas){
    if(pointerDown){//twoDown){
        canvas.drawBitmap(frame, framePts.getX(), framePts.getY(), null);
        canvas.drawBitmap(cursor, cursorPts.getX(), (cursorPts.getY()+dy), null);
    }
    invalidate();
}

private class MyPoints{

    private int x = -100;
    private int y = -100;
    private int deltaY = 0;;

    public MyPoints(){
        this.x = 0;
        this.y = 0;
    }

    public int getX(){
        return this.x;
    }

    public int getY(){
        return this.y;
    }

    public void setOrigin(int x, int y){
        this.x = x;
        this.y = y;
    }

    public int getDeltaY(){
        return deltaY;
    }

    public void setDeltaY(int newY){
        deltaY = (newY-y);
        Log.d("TouchUI", "DY: " + deltaY);
    }
}
}

Main.xml

    <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/parentLayout"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<LinearLayout android:orientation="horizontal"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <com.robota.android.TouchUI xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/leftTouchUI"
        android:background="#0000"
        android:layout_height="match_parent"
        android:layout_width="wrap_content"
        android:layout_weight="1">
    </com.robota.android.TouchUI>
    <com.robota.android.TouchUI xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/rightTouchUI"
        android:background="#0000"
        android:layout_height="match_parent"
        android:layout_width="wrap_content"
        android:layout_weight="1">
    </com.robota.android.TouchUI>
</LinearLayout>

RobotController.java（主活动类）

    package com.robota.android;

    import android.app.Activity;
    import android.bluetooth.BluetoothAdapter;
    import android.bluetooth.BluetoothDevice;
    import android.content.ActivityNotFoundException;
    import android.content.Intent;
    import android.os.Bundle;
    import android.os.Handler;
    import android.os.Message;
    import android.util.Log;
    import android.view.Menu;
    import android.view.MenuInflater;
    import android.view.MenuItem;
    import android.view.View;
    import android.view.Window;
    import android.widget.ScrollView;
    import android.widget.TextView;
    import android.widget.Toast;

public class RobotController extends Activity {
// Tag used to keep track of class in the Log
private static final String TAG = "robotController_new";
// Boolean to debugging
private static final boolean D = true;

// Intent request codes
private static final int DISCONNECT_DEVICE = 1;
private static final int CONNECT_DEVICE = 2;
private static final int REQUEST_ENABLE_BT = 3;

// Handler Codes
public static final int MESSAGE_READ = 1;
public static final int MESSAGE_WRITE = 2;

// Local Bluetooth Adapter
private BluetoothAdapter bluetoothAdapter = null;
// Bluetooth Discovery and Datahandler
private BluetoothComm btComm = null;

// Debug's TextView, this is where strings will be written to display
private TextView tv;
private ScrollView sv;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    if(D) Log.d(TAG, "++ON CREATE++");
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.main);

    bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

    if(bluetoothAdapter == null){
        if(D) Log.d(TAG, "NO BLUETOOTH DEVICE");
        Toast.makeText(this, "Bluetooth is not available", Toast.LENGTH_SHORT).show();
        finish();
        return;
    }

    PacketController.controller = this;
}


public void onStart(){
    super.onStart();
    if(D) Log.d(TAG, "++ON START++");

    if(!bluetoothAdapter.isEnabled()){
        Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
        startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
    }else{
        // Start BluetoothComm
        if(btComm == null){
            setupComm();
        }
    }
}

/**
 * Creates new Bluetooth Communication
 */
private void setupComm(){
    if(D) Log.d(TAG, "+++setupComm+++");
    btComm = new BluetoothComm(this, handler);
}

private void connectDevice(Intent data){
    if(D) Log.d(TAG, "+++connectDevice+++");
    String addr = data.getExtras()
        .getString(DeviceListActivity.EXTRA_DEVICE_ADDRESS);
    BluetoothDevice device = bluetoothAdapter.getRemoteDevice(addr);
    if(D) Log.d(TAG,"REMOTE ADDR: "+ addr);
    btComm.connect(device);
}

private void disconnectDevice(){
    if(D) Log.d(TAG, "---disconnectDevice---");
    if(btComm.getState() == btComm.STATE_CONNECTED){
        btComm.disconnect();
    }
}

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
    //super.onCreateOptionsMenu(menu);
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.menu, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    Intent serverIntent = null;
    switch(item.getItemId()){       
    case R.id.insecure_connect_scan:
        // Launch the DeviceListActivity to see devices and do scan
        serverIntent = new Intent(this, DeviceListActivity.class);
        try{
            startActivityForResult(serverIntent, CONNECT_DEVICE);
        }catch(ActivityNotFoundException activityNotFound){
            Log.e(TAG, "Could not start DeviceListActivity(Insecure)");
        }
        return true;
    }
    return false;
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data){
    switch(requestCode){
    case CONNECT_DEVICE:
        if(resultCode == Activity.RESULT_OK){
            connectDevice(data);
        }
        break;
    case DISCONNECT_DEVICE:
        if(resultCode == Activity.RESULT_OK){
            disconnectDevice();
        }
        break;
    }
}

public Handler getHandler(){
    return this.handler;
}

public BluetoothComm getBtComm(){
    return this.btComm;
}

// The Handler that gets information back from the BluetoothChatService
private final Handler handler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
        if(D) Log.d(TAG, "check message");
        switch (msg.what) {
        case MESSAGE_READ:
            if(D) Log.d(TAG, "trying to read message");
            byte[] readBuf = (byte[]) msg.obj;
            // construct a string from the valid bytes in the buffer
            String readMessage = new String(readBuf, 0, msg.arg1);
            if(D) Log.d(TAG, "bytes: " + readBuf + " arg1: " + msg.arg1 + " Message: " + readMessage);
            tv.append(readMessage);
            break;
        case MESSAGE_WRITE:
            if(D) Log.d(TAG, "trying to send message");
            String sendMessage = new String(String.valueOf(msg.obj));
        }
    }
};
}

任何未列出的其他类我认为不需要，但如果需要，请告诉我。

非常感谢任何帮助

Answer 1

您需要保存每个点的pointerId，并将它们与每个MotionEvent 给出的新Id 进行比较。解释起来有点棘手，所以我会向您指出这个 ADB Post 比我解释得更好。长话短说？多点触控可能很棘手，但它并不像乍一看那么糟糕。