[Android实例] android多点触摸demo

MultiTouchActivity Java代码

package com.zhaokai.multitouch;
import android.app.Activity;
import android.os.Bundle;
import android.view.Window;
import android.view.WindowManager;
public class MultiTouchActivity extends Activity {
/** Called when the activity is first created. */
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//隐藏标题栏
requestWindowFeature(Window.FEATURE_NO_TITLE);
//设置成全屏
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
//设置为上面的MTView
setContentView(new MySurfaceView(this));
}
}

SurfaceView类：

Java代码

package com.zhaokai.multitouch;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;
public class MySurfaceView extends SurfaceView implements Callback{
private static final int MAX_TOUCHPOINTS = 10;
private static final String START_TEXT = "请随便触摸屏幕进行测试";
private Paint textPaint = new Paint();
private Paint touchPaints[] = new Paint[MAX_TOUCHPOINTS];
private int colors[] = new int[MAX_TOUCHPOINTS];
private int width, height;
private float scale = 1.0f;
public MySurfaceView(Context context) {
super(context);
SurfaceHolder holder = getHolder();
holder.addCallback(this);
setFocusable(true); // 确保我们的View能获得输入焦点
setFocusableInTouchMode(true); // 确保能接收到触屏事件
init();
}
public void init(){
// 初始化10个不同颜色的画笔
textPaint.setColor(Color.WHITE);
colors[0] = Color.BLUE;
colors[1] = Color.RED;
colors[2] = Color.GREEN;
colors[3] = Color.YELLOW;
colors[4] = Color.CYAN;
colors[5] = Color.MAGENTA;
colors[6] = Color.DKGRAY;
colors[7] = Color.WHITE;
colors[8] = Color.LTGRAY;
colors[9] = Color.GRAY;
for(int i=0;i
touchPaints[i]=new Paint();
touchPaints[i].setColor(colors[i]);
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
int pointerCount=event.getPointerCount();
if(pointerCount>MAX_TOUCHPOINTS){
pointerCount=MAX_TOUCHPOINTS;
}
Canvas c=getHolder().lockCanvas();
if(c!=null){
c.drawColor(Color.BLACK);
if(event.getAction()==MotionEvent.ACTION_UP){
// 当手离开屏幕时，清屏
c.drawColor(Color.BLACK);
}else{
// 先在屏幕上画一个十字，然后画一个圆
for(int i=0;i
//获取一个触点的坐标，然后开始绘制
int id=event.getPointerId(i);
int x=(int)event.getX(i);
int y=(int)event.getY(i);
drawCrosshairsAndText(x, y, touchPaints[id], i, id, c);
}
for(int i=0;i
int id=event.getPointerId(i);
int x=(int)event.getX(i);
int y=(int)event.getY(i);
drawCircle(x, y, touchPaints[id],c);
}
}
getHolder().unlockCanvasAndPost(c);
}
return true;
}
private void drawCrosshairsAndText(int x, int y, Paint paint, int ptr,int id, Canvas c) {
c.drawLine(0, y, width, y, paint);
c.drawLine(x, 0, x, height, paint);
int textY = (int) ((15 + 20 * ptr) * scale);
c.drawText("x" + ptr + "=" + x, 10 * scale, textY, textPaint);
c.drawText("y" + ptr + "=" + y, 70 * scale, textY, textPaint);
c.drawText("id" + ptr + "=" + id, width - 55 * scale, textY, textPaint);
}
private void drawCircle(int x, int y, Paint paint, Canvas c) {
c.drawCircle(x, y, 40 * scale, paint);
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
this.width = width;
this.height = height;
if (width > height){
this.scale = width / 480f;
} else {
this.scale = height / 480f;
}
textPaint.setTextSize(14 * scale);
Canvas c = getHolder().lockCanvas();
if (c != null) { // 背景黑色
c.drawColor(Color.BLACK);
float tWidth = textPaint.measureText(START_TEXT);
c.drawText(START_TEXT, width / 2 - tWidth / 2, height / 2,textPaint);
getHolder().unlockCanvasAndPost(c);
}
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
}

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