Android--简单的画画板实例代码

来源：互联网发布：安装linux图形界面编辑：程序博客网时间：2024/04/30 08:15

<span style="font-size:14px;">public class MainActivity extends Activity { private ImageView iv; private Bitmap baseBitmap; private Canvas canvas; private Paint paint; @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  this.iv = (ImageView) this.findViewById(R.id.iv);  // 创建一张空白图片  baseBitmap = Bitmap.createBitmap(480, 640, Bitmap.Config.ARGB_8888);  // 创建一张画布  canvas = new Canvas(baseBitmap);  // 画布背景为灰色  canvas.drawColor(Color.GRAY);  // 创建画笔  paint = new Paint();  // 画笔颜色为红色  paint.setColor(Color.RED);  // 宽度5个像素  paint.setStrokeWidth(5);  // 先将灰色背景画上  canvas.drawBitmap(baseBitmap, new Matrix(), paint);  iv.setImageBitmap(baseBitmap);  iv.setOnTouchListener(new OnTouchListener() {   int startX;   int startY;   @Override   public boolean onTouch(View v, MotionEvent event) {    switch (event.getAction()) {    case MotionEvent.ACTION_DOWN:     // 获取手按下时的坐标     startX = (int) event.getX();     startY = (int) event.getY();     break;    case MotionEvent.ACTION_MOVE:     // 获取手移动后的坐标     int stopX = (int) event.getX();     int stopY = (int) event.getY();     // 在开始和结束坐标间画一条线     canvas.drawLine(startX, startY, stopX, stopY, paint);     // 实时更新开始坐标     startX = (int) event.getX();     startY = (int) event.getY();     iv.setImageBitmap(baseBitmap);     break;    }    return true;   }  }); } public void save(View view) {  try {   File file = new File(Environment.getExternalStorageDirectory(),     System.currentTimeMillis() + ".jpg");   OutputStream stream = new FileOutputStream(file);   baseBitmap.compress(CompressFormat.JPEG, 100, stream);   stream.close();   // 模拟一个广播，通知系统sdcard被挂载   Intent intent = new Intent();   intent.setAction(Intent.ACTION_MEDIA_MOUNTED);   intent.setData(Uri.fromFile(Environment     .getExternalStorageDirectory()));   sendBroadcast(intent);   Toast.makeText(this, "保存图片成功", 0).show();  } catch (Exception e) {   Toast.makeText(this, "保存图片失败", 0).show();   e.printStackTrace();  } }}</span>

简单的布局文件：

<span style="font-size:14px;"><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context=".MainActivity" >    <Button        android:id="@+id/button1"        android:onClick="save"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_alignParentBottom="true"        android:text="保存图片" />    <ImageView        android:layout_above="@id/button1"        android:id="@+id/iv"        android:layout_width="match_parent"        android:layout_height="match_parent"        /></RelativeLayout></span>

再来个权限：

<span style="font-size:14px;"><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/></span>

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