改变方向后以编程方式截图

Question

我正在开发一款应用程序，它可以截取布局的屏幕截图，将其保存为PDF格式，然后通过谷歌云打印将其发送。一切都很好，但我有一个问题，关于屏幕截图的方向。

对于主机片段，我做了一个横向和纵向布局。截图必须始终是纵向的，所以我们的想法是通过编程将屏幕旋转到纵向，截取截图，然后将屏幕方向设置回Sensor。我使用以下方法更改配置:

public void lockScreenOrientation(String orientation) {     
    if (orientation.contains("portrait")) {
        mActivity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);            
    } else if (orientation.contains("auto")) {
        mActivity.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR);
    }
}

截图和PDF创建发生在AsyncTask中，这是由主机片段中的确认对话框触发的

if (print) {            
        new AsyncPDF(mActivity).execute(field_client_name_txt, "birthday");
        prefs.edit().putBoolean("Print", false).commit();
}

当方向为纵向时，一切都很好!当屏幕截图和打印需要将方向旋转为纵向时，问题就发生了。截图捕捉的是风景布局的图像，而不是肖像布局的图像，最终的pdf是凌乱的和裁剪的!

参考这里是我的Asynctask:

public class AsyncPDF extends AsyncTask<String, Void, Void> {
Activity mActivity;
Context mContext;
private static final int REQUEST_CODE = 4;
private static String SDCARD = Environment.getExternalStorageDirectory().getPath();
private static String DIRECTORY = SDCARD + "/Amorino";
private static String DIR_CACHE = DIRECTORY + "/Cache/";
private static String DIR_BIRTHDAY_ORDERS = DIRECTORY + "/Orders/Birthday/";
private static String DIR_WEDDING_ORDERS = DIRECTORY + "/Orders/Wedding/";
private static String DIR_OTHER_ORDERS = DIRECTORY + "/Orders/Other/";
private static String DIR_PRODUCTION = DIRECTORY + "/Production/";
String pdfName, pdfType = "";
Utils mUtility;
public AsyncPDF(Activity activity) {
    this.mActivity = activity;
    this.mContext = activity;
}
@Override
protected void onPreExecute() {
    mUtility = new Utils(mContext);
    Toast.makeText(mActivity, "Αποθήκευση αρχείου...", Toast.LENGTH_SHORT)
            .show();
        screenCapture();
};
@Override
protected Void doInBackground(String... params) {
    pdfName = params[0];
    pdfType = params[1];
    createPdf();
    return null;
}
@Override
protected void onProgressUpdate(Void... values) {
    super.onProgressUpdate(values);
}
@Override
protected void onPostExecute(Void result) {
    super.onPostExecute(result);
    clearCacheFolder(); 
    Toast.makeText(mActivity, "Το αρχείο αποθηκέυτηκε επιτυχώς!",
            Toast.LENGTH_SHORT).show();
}
private void screenCapture() {
    try {
        ScrollView mLayoutRoot = (ScrollView) mActivity
                .findViewById(R.id.print_screen_layout);
        mLayoutRoot.setDrawingCacheEnabled(true);
        mLayoutRoot.buildDrawingCache();
        Bitmap mBitmap = mLayoutRoot.getDrawingCache();
        File file, f = null;
        if (android.os.Environment.getExternalStorageState().equals(
                android.os.Environment.MEDIA_MOUNTED)) {
            file = new File(DIR_CACHE);
            if (!file.exists()) {
                file.mkdirs();
            }
            f = new File(file.getAbsolutePath() + File.separator
                    + "temp_layout" + ".png");
        }
        FileOutputStream ostream = new FileOutputStream(f);
        mBitmap.compress(CompressFormat.PNG, 10, ostream);
        ostream.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
}
private void createPdf() {
    Document document = new Document();
    Image header_img, main_img;
    InputStream inputStream_header = null;
    String current_directory = "";
    try {
        AssetManager mngr = mContext.getAssets();
        if (pdfType.contains("birthday")) {
            inputStream_header = mngr.open("header_birthday.png");
            current_directory = DIR_BIRTHDAY_ORDERS;
        } else if (pdfType.contains("wedding")) {
            inputStream_header = mngr.open("header_wedding.png");
            current_directory = DIR_WEDDING_ORDERS;
        } else if (pdfType.contains("other")) {
            inputStream_header = mngr.open("header_order.png");
            current_directory = DIR_OTHER_ORDERS;
        } else if (pdfType.contains("production")) {
            inputStream_header = mngr.open("header_order.png");
            current_directory = DIR_PRODUCTION;
        }
        File file = new File(current_directory);
        if (!file.exists()) {
            file.mkdirs();
        }
        PdfWriter.getInstance(document, new FileOutputStream(
                current_directory + "/" + pdfName + ".pdf"));
        document.open();
        Bitmap bmp = BitmapFactory.decodeStream(inputStream_header);
        ByteArrayOutputStream stream_header = new ByteArrayOutputStream();
        bmp.compress(Bitmap.CompressFormat.PNG, 100, stream_header);
        header_img = Image.getInstance(stream_header.toByteArray());
        header_img.scalePercent(24f);
        header_img.setAbsolutePosition(-1f, 750f);
        document.add(header_img);
        Paragraph paragraph = new Paragraph(
                header_img.getScaledHeight() + 50f);
        document.add(paragraph);
        main_img = Image.getInstance(DIR_CACHE
                + "/temp_layout.png");
        main_img.scaleToFit(520f, 2000f);
        main_img.setAlignment(Image.ALIGN_CENTER);
        Log.d("Original Width: ", String.valueOf(main_img.getWidth()));
        Log.d("Original Height ", String.valueOf(main_img.getHeight()));
        Log.d("Scaled Width: ", String.valueOf(main_img.getScaledWidth()));
        Log.d("Scaled Height ", String.valueOf(main_img.getScaledHeight()));
        document.add(main_img);
        document.close();
        File f = new File(current_directory + "/" + pdfName + ".pdf");
        printPdf(f, pdfName);
    } catch (Exception e) {
        e.printStackTrace();
    }
}
private void printPdf(File f, String name) {
    Uri docUri = Uri.fromFile(f);
    Intent printIntent = new Intent(mContext, PrintDialogActivity.class);
    printIntent.setDataAndType(docUri, "application/pdf");
    printIntent.putExtra("title", name + ".pdf");
    mActivity.startActivityForResult(printIntent, REQUEST_CODE);
}
private void clearCacheFolder() {
    File dir = new File(DIR_CACHE);
    if (dir.isDirectory()) {
        String[] children = dir.list();
        for (int i = 0; i < children.length; i++) {
            new File(dir, children[i]).delete();
        }
    }
}

}

我认为故障发生在mActivity参数上。我认为它传递了原始景观布局的片段，而不是纵向布局。我试图使用存储在SharedPreference中的"打印"标志，然后从onResume方法执行AsyncTask，没有运气。屏幕截图仍然是横向布局。什么好主意吗?

在片段生命周期的哪一点之后，我应该执行AsyncTask，以获得适当的(肖像)布局?

注:第一个问题!!

Answer 1

我终于在一个星期前弄明白了，这是解决方案!

这个问题用这个答案的提示解决了。我添加了一个GlobalLayoutListener，以便在新布局解决后启动AsyncPDF类，问题几乎解决了。后来我不得不处理一个新问题…!

PDF现在打印了正确的布局，但是一些EditText字段显示为空!!在经历了很多挫折、挠头和反复试验之后，我找到了问题所在。GlobalLayoutListener按预期工作，但似乎它启动打印功能有点太早了，因此字段没有时间被正确绘制/填充。

为了解决这个问题，我使用Handler类添加了最小延迟(100ms)，之后一切都像他们应该的那样工作!下面是print方法的代码:

public void print(String orientation) {
    print = prefs.getBoolean("print", false);
    if (print)
        if (orientation.contains("portrait")) {
            new AsyncPDF(mActivity, v).execute(field_client_name_txt,
                    "birthday");
        } else {
            ViewTreeObserver observer = v.getViewTreeObserver();
            observer.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
                @Override
                public void onGlobalLayout() {
                    /* Adds a minimal wait time for the view to settle */
                    final Handler handler = new Handler();
                    handler.postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            new AsyncPDF(mActivity, v).execute(
                                    field_client_name_txt, "birthday");
                        }
                    }, 100);
                    v.getViewTreeObserver().removeOnGlobalLayoutListener(
                            this);
                }
            });
        }
    /* Reset the print flag to false */
    prefs.edit().putBoolean("print", false).commit();
}

该方法从ActionBar中的打印按钮启动，如果我们已经在Portrait中，它会启动AsyncPDF类imm。在横向的情况下，它等待纵向布局解决，然后添加一个100ms的延迟，然后它启动AsyncTask。

public void onClick(DialogInterface dialog, int id) {
     prefs.edit().putBoolean("print", true).commit();
     if (mUtility.getScreenOrientation() == 1)
          print("portrait");
     else
          mUtility.lockScreenOrientation("portrait");
     }
});

print(String orientation)方法，被放置在onActivityCreated()方法中，所以当配置发生变化时，它会检查打印标志是否被触发并相应地采取行动。