该文章属于原创,转载注明出处:http://www.pm-road.com/index.php/2014/10/29/140/
安卓可以通过Bitmap对象可以实现对整个屏幕的截屏,同时也可以通过该类实现对局部屏幕的截屏,
其中的主要原理就是通过手指对屏幕的onTouch操作:如按下屏幕,在屏幕上移动 ,从屏幕上起来等;
而一般性的截图在截图过程中,选中的屏幕颜色会改变,所以该功能在选取过程中,为了方便看到选择的屏幕大小,我们也会改变屏幕的颜色;
根据思路,如果要在屏幕选择过程中,某个局部显示的屏幕颜色不同,我们需要在当前View里面加入一个View对象,
所以我们应该先写一个类:ScreenShotView.java 该类应该继续View对象,具体代码如下:
package com.titan_geo.view; import android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Rect; import android.view.View; public class ScreenShotView extends View { private int x;//手指按下去的x坐标 private int y;//手指按下去的y坐标 private int m;//手指弹起的x坐标 private int n;//手指弹起的的y坐标 private boolean sign;//是否可以进行截屏操作 private Paint paint;//将选取的屏幕画颜色 public ScreenShotView(Context context) { super(context); paint = new Paint(Paint.FILTER_BITMAP_FLAG); } @Override protected void onDraw(Canvas canvas) { if(sign){ paint.setColor(Color.TRANSPARENT);//白 }else{ paint.setColor(Color.RED);//将选取的屏幕设置成红色 paint.setAlpha(80);//透明度80 canvas.drawRect(new Rect(x, y, m, n), paint); } super.onDraw(canvas); } public void setSeat(int x,int y,int m,int n){ this.x = x; this.y = y; this.m = m; this.n = n; } public boolean isSign() { return sign; } public void setSign(boolean sign) { this.sign = sign; } }
该文章属于原创,转载注明出处:http://www.pm-road.com/index.php/2014/10/29/140/
然后在要截屏的activity中加入相应的代码:(比如说:MainActivity.java)
// 截图属性 private int screenshot_x;// 绘画开始的横坐标 private int screenshot_y;// 绘画开始的纵坐标 private int screenshot_m;// 绘画结束的横坐标 private int screenshot_n;// 绘画结束的纵坐标 private int screenshot_width;// 绘画的宽度 private int screenshot_height;// 绘画的高度 private Bitmap screenshot_bitmap;// 生成的位图 private ScreenShotView screenshotView;// 绘画选择区域 private String screenUrl; private Context context; private ImageView image1;//需要截图的图片 在此(MainActivity.java)的oncreate方法中增加如下代码: //将截屏的view 要放在该activity中 screenshotView= new ScreenShotView(this); image1 = (ImageView) findViewById(R.id.image1);//需要截屏的部分,可以是任何view对象 //声明一个对话框,提示可以开始截屏了 new AlertDialog.Builder(this) .setMessage(“选取屏幕开始截屏”) .setPositiveButton(“确定”,new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialoginterface,int i) { screenshotView.setSign(true);//当按下确定按钮时,将截屏中的方法设置为true if (myView.isSign()) { screenshotView.setSeat(0, 0, 0, 0); screenshotView.setSign(false); } else { screenshotView.setSign(true); } screenshotView.postInvalidate(); } }).show(); //将截屏的内容放在该activity中 this.addContentView(screenshotView, new LayoutParams( LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
然后对image1增加ontouch事件:
image1.setOnTouchListener(new ScreenShotListener());//声明一个内部类的事件
内部类代码如下:
class ScreenShotListener implements OnTouchListener { @Override public boolean onTouch(View v, MotionEvent event) { if (event.getAction() == MotionEvent.ACTION_DOWN) { screenshot_x = 0; screenshot_y = 0; screenshot_width = 0; screenshot_height = 0; screenshot_x = (int) event.getX(); screenshot_y = (int) event.getY(); } if (event.getAction() == MotionEvent.ACTION_MOVE) { screenshot_m = (int) event.getX(); screenshot_n = (int) event.getY(); screenshotView.setSeat(screenshot_x, screenshot_y, screenshot_m, screenshot_n); screenshotView.postInvalidate(); } if (event.getAction() == MotionEvent.ACTION_UP) { if (event.getX() > screenshot_x) { screenshot_width = (int) event.getX() – screenshot_x; } else { screenshot_width = (int) (screenshot_x – event.getX()); screenshot_x = (int) event.getX(); } if (event.getY() > screenshot_y) { screenshot_height = (int) event.getY() – screenshot_y; } else { screenshot_height = (int) (screenshot_y – event.getY()); screenshot_y = (int) event.getY(); } new AlertDialog.Builder(context) .setMessage(“确定截图”) .setPositiveButton(“确定”, new DialogInterface.OnClickListener() { public void onClick( DialogInterface dialoginterface, int i) { //截图完毕之后,会提示是否保存所需要的图片,如果点确定 ,则执行此方法 saveBitmap();//具体代码如下 } }).setNegativeButton(“取消”, null).show(); } if (screenshotView.isSign()) { return false; } else { return true; } } } /** * 保存位图 * * @param activity * @return */ private void saveBitmap() { View view = this.getWindow().getDecorView(); view.setDrawingCacheEnabled(true); view.buildDrawingCache(); screenshot_bitmap = view.getDrawingCache(); Rect frame = new Rect(); this.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame); int toHeight = frame.top; screenshot_bitmap = Bitmap.createBitmap(screenshot_bitmap, screenshot_x, screenshot_y + 2 * toHeight, screenshot_width, screenshot_height); try { FileOutputStream fout = new FileOutputStream(screenUrl);//这里screenUrl是保存图片的路径 ,在这里需要声明一下,否则会报错 screenshot_bitmap.compress(Bitmap.CompressFormat.PNG, 100, fout); if(fout != null){ fout.close(); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } view.setDrawingCacheEnabled(false); }
代码完毕,该文章属于原创,转载注明出处:http://www.pm-road.com/index.php/2014/10/29/140/