[Android應用開發]-（13）屏幕截圖功能--截取全屏，無需Root（附源碼）

由於要做說明書，或者給客戶看效果圖，不得不通過截圖的方式把屏幕接下來（當然了，還可以通過拍照來達到目的）。於是就Google找到一些需要Root權限，和不需要Root權限的截圖應用，有些失望，多數不可用。於是就想自己開發一個截圖的應用。在View 中提供一個getDrawingCache的方法，可以通過次方法獲取View的截屏，但僅僅是截取View的。如果要截取狀態欄呢？

    其實不然，在ICS中的SystemUI就實現了截圖的功能，按組合鍵Power+Volume Add/Volume sub就能截取圖片。代碼目錄：
frameworks/base/packages/SystemUI/src/com/android/systemui/screenshot/在此目錄下就兩個文件，主要的截圖方法在GlobalScreenshot中，本文就通過移植SystemUI中截圖的代碼實現截圖功能。

    首先是直接移植SystemUI的代碼，實現截圖效果，這部分的代碼就不貼出來了，直接去下載代碼吧， 關鍵的代碼沒有幾句，最最主要的是：Surface.screenshot()，請看代碼吧。

[java]
<SPAN style="FONT-SIZE: 16px">package org.winplus.ss; 
 
import java.io.File; 
import java.io.FileNotFoundException; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.text.SimpleDateFormat; 
import java.util.Date; 
 
import android.app.Activity; 
import android.content.Context; 
import android.graphics.Bitmap; 
import android.graphics.Canvas; 
import android.graphics.Matrix; 
import android.os.Bundle; 
import android.util.DisplayMetrics; 
import android.util.Log; 
import android.view.Display; 
import android.view.Surface; 
import android.view.WindowManager; 
import android.os.SystemProperties; 
 
public class SimpleScreenshotActivity extends Activity { 
 
    private Display mDisplay; 
    private WindowManager mWindowManager; 
    private DisplayMetrics mDisplayMetrics; 
    private Bitmap mScreenBitmap; 
    private Matrix mDisplayMatrix; 
 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.main); 
 
        new Thread(new Runnable() { 
 
            @Override 
            public void run() { 
                takeScreenshot(); 
 
            } 
        }).start(); 
    } 
 
    private float getDegreesForRotation(int value) { 
        switch (value) { 
        case Surface.ROTATION_90: 
            return 360f - 90f; 
        case Surface.ROTATION_180: 
            return 360f - 180f; 
        case Surface.ROTATION_270: 
            return 360f - 270f; 
        } 
        return 0f; 
    } 
 
    private void takeScreenshot() { 
        mWindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE); 
        mDisplay = mWindowManager.getDefaultDisplay(); 
        mDisplayMetrics = new DisplayMetrics(); 
        mDisplay.getRealMetrics(mDisplayMetrics); 
        mDisplayMatrix = new Matrix(); 
        float[] dims = { mDisplayMetrics.widthPixels, 
                mDisplayMetrics.heightPixels }; 
 
        int value = mDisplay.getRotation(); 
        String hwRotation = SystemProperties.get("ro.sf.hwrotation", "0"); 
        if (hwRotation.equals("270") || hwRotation.equals("90")) { 
            value = (value + 3) % 4; 
        } 
        float degrees = getDegreesForRotation(value); 
 
        boolean requiresRotation = (degrees > 0); 
        if (requiresRotation) { 
            // Get the dimensions of the device in its native orientation  
            mDisplayMatrix.reset(); 
            mDisplayMatrix.preRotate(-degrees); 
            mDisplayMatrix.mapPoints(dims); 
 
            dims[0] = Math.abs(dims[0]); 
            dims[1] = Math.abs(dims[1]); 
        } 
 
        mScreenBitmap = Surface.screenshot((int) dims[0], (int) dims[1]); 
 
        if (requiresRotation) { 
            // Rotate the screenshot to the current orientation  
            Bitmap ss = Bitmap.createBitmap(mDisplayMetrics.widthPixels, 
                    mDisplayMetrics.heightPixels, Bitmap.Config.ARGB_8888); 
            Canvas c = new Canvas(ss); 
            c.translate(ss.getWidth() / 2, ss.getHeight() / 2); 
            c.rotate(degrees); 
            c.translate(-dims[0] / 2, -dims[1] / 2); 
            c.drawBitmap(mScreenBitmap, 0, 0, null); 
            c.setBitmap(null); 
            mScreenBitmap = ss; 
        } 
 
        // If we couldn't take the screenshot, notify the user  
        if (mScreenBitmap == null) { 
            return; 
        } 
 
        // Optimizations  
        mScreenBitmap.setHasAlpha(false); 
        mScreenBitmap.prepareToDraw(); 
         
        try { 
            saveBitmap(mScreenBitmap); 
        } catch (IOException e) { 
            System.out.println(e.getMessage()); 
        } 
    } 
 
    public void saveBitmap(Bitmap bitmap) throws IOException { 
        String imageDate = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss") 
                .format(new Date(System.currentTimeMillis())); 
        File file = new File("/mnt/sdcard/Pictures/"+imageDate+".png"); 
        if(!file.exists()){ 
            file.createNewFile(); 
        } 
        FileOutputStream out; 
        try { 
            out = new FileOutputStream(file); 
            if (bitmap.compress(Bitmap.CompressFormat.PNG, 70, out)) { 
                out.flush(); 
                out.close(); 
            } 
        } catch (FileNotFoundException e) { 
            e.printStackTrace(); 
        } catch (IOException e) { 
            e.printStackTrace(); 
        } 
    } 
} 
</SPAN> 

package org.winplus.ss;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Display;
import android.view.Surface;
import android.view.WindowManager;
import android.os.SystemProperties;

public class SimpleScreenshotActivity extends Activity {

 private Display mDisplay;
 private WindowManager mWindowManager;
 private DisplayMetrics mDisplayMetrics;
 private Bitmap mScreenBitmap;
 private Matrix mDisplayMatrix;

 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);

  new Thread(new Runnable() {

   @Override
   public void run() {
    takeScreenshot();

   }
  }).start();
 }

 private float getDegreesForRotation(int value) {
  switch (value) {
  case Surface.ROTATION_90:
   return 360f - 90f;
  case Surface.ROTATION_180:
   return 360f - 180f;
  case Surface.ROTATION_270:
   return 360f - 270f;
  }
  return 0f;
 }

 private void takeScreenshot() {
  mWindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
  mDisplay = mWindowManager.getDefaultDisplay();
  mDisplayMetrics = new DisplayMetrics();
  mDisplay.getRealMetrics(mDisplayMetrics);
  mDisplayMatrix = new Matrix();
  float[] dims = { mDisplayMetrics.widthPixels,
    mDisplayMetrics.heightPixels };

  int value = mDisplay.getRotation();
  String hwRotation = SystemProperties.get("ro.sf.hwrotation", "0");
  if (hwRotation.equals("270") || hwRotation.equals("90")) {
   value = (value + 3) % 4;
  }
  float degrees = getDegreesForRotation(value);

  boolean requiresRotation = (degrees > 0);
  if (requiresRotation) {
   // Get the dimensions of the device in its native orientation
   mDisplayMatrix.reset();
   mDisplayMatrix.preRotate(-degrees);
   mDisplayMatrix.mapPoints(dims);

   dims[0] = Math.abs(dims[0]);
   dims[1] = Math.abs(dims[1]);
  }

  mScreenBitmap = Surface.screenshot((int) dims[0], (int) dims[1]);

  if (requiresRotation) {
            // Rotate the screenshot to the current orientation
            Bitmap ss = Bitmap.createBitmap(mDisplayMetrics.widthPixels,
                    mDisplayMetrics.heightPixels, Bitmap.Config.ARGB_8888);
            Canvas c = new Canvas(ss);
            c.translate(ss.getWidth() / 2, ss.getHeight() / 2);
            c.rotate(degrees);
            c.translate(-dims[0] / 2, -dims[1] / 2);
            c.drawBitmap(mScreenBitmap, 0, 0, null);
            c.setBitmap(null);
            mScreenBitmap = ss;
        }

        // If we couldn't take the screenshot, notify the user
        if (mScreenBitmap == null) {
            return;
        }

        // Optimizations
        mScreenBitmap.setHasAlpha(false);
        mScreenBitmap.prepareToDraw();
       
  try {
   saveBitmap(mScreenBitmap);
  } catch (IOException e) {
   System.out.println(e.getMessage());
  }
 }

 public void saveBitmap(Bitmap bitmap) throws IOException {
  String imageDate = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss")
    .format(new Date(System.currentTimeMillis()));
  File file = new File("/mnt/sdcard/Pictures/"+imageDate+".png");
  if(!file.exists()){
   file.createNewFile();
  }
  FileOutputStream out;
  try {
   out = new FileOutputStream(file);
   if (bitmap.compress(Bitmap.CompressFormat.PNG, 70, out)) {
    out.flush();
    out.close();
   }
  } catch (FileNotFoundException e) {
   e.printStackTrace();
  } catch (IOException e) {
   e.printStackTrace();
  }
 }
}

PS：1、需要在AndroidManifest.xml中加入代碼：android:sharedUserId="android.uid.system"

         2、由於調用了@hide的API，所以編譯得時候請使用makefile編譯。或者通過在Eclipse中添加Jar文件通過編譯。

         3、此代碼只在Android4.0中使用過，2.3的就沒去做測試了。

 作者：tangcheng_ok