android on touch畫線

Question

我有一個獲取圖像視圖座標的代碼，當用戶在imageview中觸摸2次時，我想畫一條線。 imageview有一個可繪製的位圖。更多的細節，這是我的代碼：

public class MainActivity extends Activity implements OnTouchListener { 
    ImageView tampil; 
    Matrix matrix = new Matrix(); 
    Matrix savedMatrix = new Matrix(); 
    private static final String TAG = "Touch"; 
    static final int NONE = 0; 
    static final int DRAG = 1; 
    static final int ZOOM = 2; 
    int mode = NONE; 

    // Remember some things for zooming 
    PointF start = new PointF(); 
    PointF mid = new PointF(); 
    float oldDist = 1f; 
    float x1, y1, x2, y2; 
    Bitmap bmp; 
    int i = 1; 



@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    tampil = (ImageView)findViewById(R.id.imageView1); 
    tampil.setOnTouchListener(this); 
    Drawable d = getResources().getDrawable(R.drawable.enigma); 
    bmp = ((BitmapDrawable)d).getBitmap(); 
    tampil.setImageBitmap(bmp); 
} 

@Override 
public boolean onTouch(View v, MotionEvent event) { 
    // TODO Auto-generated method stub 
    //ImageView view = (ImageView) v; 

     // Handle touch events here... 
     switch (event.getAction() & MotionEvent.ACTION_MASK) { 
     case MotionEvent.ACTION_DOWN: 
     savedMatrix.set(matrix); 
     start.set(event.getX(), event.getY()); 
     Log.d(TAG, "mode=DRAG"); 
     mode = DRAG; 
     Log.i(TAG, "("+String.valueOf((int)event.getX())+","+String.valueOf((int)event.getY())+")"); 
     if (i==1){ 
      x1 = event.getX(); 
      y1 = event.getY(); 
      i = 2; 
      Log.i(TAG, "coordinate x1 : "+String.valueOf(x1)+" y1 : "+String.valueOf(y1)); 
     } else if (i==2){ 
      x2 = event.getX(); 
      y2 = event.getY(); 
      i = 3; 
      Log.i(TAG, "coordinate x2 : "+String.valueOf(x2)+" y2 : "+String.valueOf(y2)); 
      onDraw(); 
     } 
     break; 
     } 
    return true; 
} 

public void onDraw(){ 
    Bitmap tes = Bitmap.createBitmap(bmp.getWidth(), bmp.getHeight(), Bitmap.Config.RGB_565); 
    tes = bmp; 
    Canvas cvs = new Canvas(tes); 
    Paint pnt = new Paint(); 
    pnt.setColor(Color.RED); 
    Log.i(TAG, "draw line"); 
    cvs.drawLine(x1, y1, x2, y2, pnt); 
    i=1; 
    tampil.setImageBitmap(tes); 
} 
} 

但是當用戶觸摸2時，aplication沒有劃清界線..任何人都可以給一個解決方案

這是日誌貓說：

10-17 12:08:21.082: I/ActivityManager(70): Displayed com.example.tesontouch/.MainActivity: +3s139ms 
    10-17 12:08:24.103: D/Touch(796): mode=DRAG 
    10-17 12:08:24.103: I/Touch(796): (113,145) 
    10-17 12:08:24.123: I/Touch(796): coordinate x1 : 113.26723 y1 : 145.2766 
    10-17 12:08:26.243: D/dalvikvm(264): GC_EXPLICIT freed 8K, 55% free 2595K/5703K, external 1625K/2137K, paused 88ms 
    10-17 12:08:26.323: D/Touch(796): mode=DRAG 
    10-17 12:08:26.323: I/Touch(796): (306,284) 
    10-17 12:08:26.343: I/Touch(796): coordinate x2 : 306.67017 y2 : 284.45056 
    10-17 12:08:26.423: D/dalvikvm(796): GC_EXTERNAL_ALLOC freed 4K, 53% free 2559K/5379K, external 3064K/4342K, paused 81ms 
    10-17 12:08:26.473: I/Touch(796): draw line 
    10-17 12:08:31.413: D/dalvikvm(473): GC_EXPLICIT freed 6K, 52% free 2697K/5511K, external 3502K/4752K, paused 183ms 

Answer 1

這是正確的工作代碼:)

package com.example.stackdrawline; 

import android.os.Bundle; 
import android.app.Activity; 
import android.graphics.Bitmap; 
import android.graphics.Bitmap.Config; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Matrix; 
import android.graphics.Paint; 
import android.graphics.PointF; 
import android.graphics.drawable.BitmapDrawable; 
import android.graphics.drawable.Drawable; 
import android.util.Log; 
import android.view.MotionEvent; 
import android.view.View; 
import android.view.View.OnTouchListener; 
import android.widget.ImageView; 

public class StackActivity extends Activity implements OnTouchListener { 
ImageView tampil; 
    Matrix matrix = new Matrix(); 
    Matrix savedMatrix = new Matrix(); 
    private static final String TAG = "Touch"; 
    static final int NONE = 0; 
    static final int DRAG = 1; 
    static final int ZOOM = 2; 
    int mode = NONE; 

    // Remember some things for zooming 
    PointF start = new PointF(); 
    PointF mid = new PointF(); 
    float oldDist = 1f; 
    float x1, y1, x2, y2; 
    Bitmap bmp; 
    int i = 1; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_stack); 
    tampil = (ImageView)findViewById(R.id.imageView1); 
    tampil.setOnTouchListener(this); 
    Drawable d = getResources().getDrawable(R.drawable. enigma); 
    bmp = ((BitmapDrawable)d).getBitmap(); 
    tampil.setImageBitmap(bmp); 

} 

@Override 
public boolean onTouch(View v, MotionEvent event) { 
    // TODO Auto-generated method stub 
    switch (event.getAction() & MotionEvent.ACTION_MASK) { 
     case MotionEvent.ACTION_DOWN: 
     savedMatrix.set(matrix); 
     start.set(event.getX(), event.getY()); 
     Log.d(TAG, "mode=DRAG"); 
     mode = DRAG; 
     Log.i(TAG, "("+String.valueOf((int)event.getX())+","+String.valueOf((int)event.getY())+")"); 
     if (i==1){ 
      x1 = event.getX(); 
      y1 = event.getY(); 
      i = 2; 
      Log.i(TAG, "coordinate x1 : "+String.valueOf(x1)+" y1 : "+String.valueOf(y1)); 
     } else if (i==2){ 
      x2 = event.getX(); 
      y2 = event.getY(); 
      i = 3; 
      Log.i(TAG, "coordinate x2 : "+String.valueOf(x2)+" y2 : "+String.valueOf(y2)); 
      onDraw(); 
     } 
     break; 
     } 
    return true; 
} 
public void onDraw(){ 
    bmp = Bitmap.createBitmap(tampil.getWidth(), tampil.getHeight(), Config.ARGB_8888); 
    Canvas c = new Canvas(bmp); 
    tampil.draw(c); 

    Paint pnt = new Paint(); 
    pnt.setColor(Color.RED); 
    c.drawLine(x1, y1, x2, y2, pnt); 
    tampil.setImageBitmap(bmp); 
    i = 1; 
} 

}