Android：如何在android编程中截图然后保存到外部存储？

Question

我在android中创建一个应用程序，用户通过触摸屏幕创建一个图形，然后将其保存到存储。

我的问题是，有时目录不会创建，有时图像会保存，但有很多图像保存在黑色图像的目录中。

主要文件保存操作发生在getDrawnMessage（）方法中。

这里是我的代码

import java.io.File; 
import java.io.FileNotFoundException; 
import java.io.FileOutputStream; 

import android.content.Context; 
import android.content.Intent; 
import android.graphics.Bitmap; 
import android.graphics.Bitmap.CompressFormat; 
import android.graphics.Bitmap.Config; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.graphics.Path; 
import android.graphics.RectF; 
import android.os.Environment; 
import android.view.MotionEvent; 
import android.view.View; 

public class DrawWrite extends View { 
float TouchXD = 0, TouchYD = 0, TouchXU = 0, TouchYU = 0, TouchXM = 0, 
     TouchYM = 0; // Define touch co-ordinates 
float x1 = 0, y1 = 0, x2 = 0, y2 = 0; // Define drawing path co-ordinates 
float stroke = 2; // Define the message structure width 
int i=0; 
boolean Move = false, moveD = false, moveU = false; // Define whether the 
                // touch has occurred or 
                // not 
boolean exp = false; 
Paint paint = new Paint(); // Paint object 
Path mPath = new Path(); // Define the drawing message path 
Context context; 

public DrawWrite(Context context) { 
    super(context); 
    this.context=context; 
} 

@Override 
public void onDraw(Canvas canvas) { 
    super.onDraw(canvas); 
    invalidate(); 
    paint.setAntiAlias(true); 
    if (DrawWriteActivity.clearScreen){ 
     mPath.reset(); 
     DrawWriteActivity.clearScreen = false; 
    } 
    cleanButton(canvas); 
    try { 
     getDrawnMessage(canvas); 
    } catch (FileNotFoundException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 
    paint.setColor(Color.parseColor(DrawWriteActivity.colorProvider)); 
    paint.setStyle(Paint.Style.STROKE); 
    paint.setStrokeWidth(DrawWriteActivity.strokeProvider); 
    if (moveD == true) { 
     x1 = TouchXD; 
     y1 = TouchYD; 
     moveD = false; 
    } else if (Move == true) { 
     x2 = TouchXD; 
     y2 = TouchYD; 
     mPath.moveTo(x1, y1); 
     mPath.lineTo(x2, y2); 
     canvas.drawPath(mPath, paint); 
     x1 = x2; 
     y1 = y2; 
    } 
} 

@Override 
public boolean onTouchEvent(MotionEvent event) { 
    switch (event.getAction()) { 
    case MotionEvent.ACTION_DOWN: 
     TouchXD = (float) event.getX(); 
     TouchYD = (float) event.getY(); 
     moveD = true; 
     break; 
    case MotionEvent.ACTION_UP: 
     TouchXU = (float) event.getX(); 
     TouchYU = (float) event.getY(); 
     moveU = true; 
     break; 
    case MotionEvent.ACTION_MOVE: 
     TouchXD = (float) event.getX(); 
     TouchYD = (float) event.getY(); 
     Move = true; 
     break; 
    } 
    return true; 
} 

public void getDrawnMessage(Canvas canvas) throws FileNotFoundException{ 
    if(exp){ 
     Bitmap bitmap = null; 
     String root = Environment.getExternalStorageDirectory().toString(); 
     File imgDir = new File(root+"/ChitBak/"); 
     String imgName; 
     bitmap = Bitmap.createBitmap(getWidth(), getHeight(), Config.ARGB_8888); 
     imgDir.mkdirs(); 
     imgName = "img"+i+".jpg"; 
     i++; 
     File file = new File(imgDir,imgName); 
     if(file.exists()) file.delete(); 
     FileOutputStream outImg = new FileOutputStream(file); 
     bitmap.compress(CompressFormat.JPEG, 100, outImg); 
     exp = false; 
     Intent in = new Intent(context, MainActivity.class); 
     in.setFlags(Intent.FLAG_ACTIVITY_NO_HISTORY); 
     context.startActivity(in); 
    } 
} 

private void cleanButton(Canvas canvas) { 
    paint.setStyle(Paint.Style.FILL); 
    paint.setColor(Color.DKGRAY); 
    canvas.drawRoundRect(new RectF(getWidth() - 100, getHeight() - 70, 
      getWidth() - 20, getHeight() - 20), 10, 10, paint); 
    paint.setColor(Color.LTGRAY); 
    paint.setTextSize(27); 
    paint.setTextSkewX((float) 0.2); 
    canvas.drawText("Save", getWidth() - 92, getHeight() - 35, paint); 
} 

private void isResetRequested() { 
    if (TouchXD >= (getWidth() - 100) && TouchYD >= getHeight() - 70 
      && TouchXD <= (getWidth() - 20) && TouchYD <= getHeight() - 20){ 
     exp = true; 
    } 
} 
} 

请帮助我的朋友，因为我不知道如何解决这个问题。

在此先感谢。

如果你想要代码中的任何东西，然后告诉我，我会提供它。

Answer 1

我认为你的捕获方法是错误的。

保存视图作为位图

这里是我使用转储整个视图为Bitmap（这将不保存通知栏，也没有导航栏）代码：

final DisplayMetrics displayMetrics = ApplicationHelper.resources().getDisplayMetrics(); 
    if (displayMetrics == null) { 
     LogHelper.warning("DisplayMetrics was NULL"); 
     return null; 
    } 

    view.setLayoutParams(new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT)); 
    view.measure(displayMetrics.widthPixels, displayMetrics.heightPixels); 
    view.layout(0, 0, displayMetrics.widthPixels, displayMetrics.heightPixels); 
    view.buildDrawingCache(); 

    final Bitmap bitmap = Bitmap.createBitmap(view.getMeasuredWidth(), view.getMeasuredHeight(), Bitmap.Config.ARGB_8888); 
    final Canvas canvas = new Canvas(bitmap); 
    view.draw(canvas); 
    return bitmap; 

请记住，您可以使用android.R.id.content来获取整个应用程序的屏幕空间，如View。

保存到外部存储

随着file.mkdirs()您的代码应工作。