Question

我正在处理android中的一个奇怪的事情。我的代码以前工作到几天前停止工作。我从库中选择一个图像，并希望得到它的Bitmap对象。我的代码：

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

位图现在为空（用于工作），我真的不知道出了什么问题。没有改变我的代码。有人有这个问题吗？谢谢。

我有权限：

 private HashSet<TextView> getTextViews(ViewGroup root){
    HashSet<TextView> views=new HashSet<>();
    for(int i=0;i<root.getChildCount();i++){
        View v=root.getChildAt(i);
        if(v instanceof TextView){
            if (((TextView) v).getText().equals("YOUR_STRING")){
                views.add((TextView)v);
            }
        }
    }
    return views;
}

Answer 1

您需要从第一行删除评论，它应该如下所示

imgDecodableString = "/storage/emulated/0/DCIM/Camera/IMG_20160114_141351594.jpg"

Bitmap decodedBitmap = BitmapFactory.decodeFile(imgDecodableString);
Log.d(Constants.TAG, "decodedBitmap: " + decodedBitmap);

Answer 2

if (CheckPermission(youractivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
// you have permission go ahead

String  imgDecodableString = "/storage/emulated/0/DCIM/Camera/IMG_20160114_141351594.jpg";

if(new File(imgDecodableString).exists()){
Bitmap decodedBitmap = BitmapFactory.decodeFile(imgDecodableString);
Log.d("Tag", "decodedBitmap: " + decodedBitmap);}
} else {
// you do not have permission go request runtime permissions
RequestPermission(youractivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE, REQUEST_RUNTIME_PERMISSION);
}



@Override
public void onRequestPermissionsResult(int permsRequestCode, String[] permissions, int[] grantResults) {

    switch (permsRequestCode) {

        case REQUEST_RUNTIME_PERMISSION: {
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

            } else {
                // you do not have permission show toast.
            }
            return;
        }
    }
}
public void RequestPermission(Activity thisActivity, String Permission, int Code) {
    if (ContextCompat.checkSelfPermission(thisActivity,
            Permission)
            != PackageManager.PERMISSION_GRANTED) {
        if (ActivityCompat.shouldShowRequestPermissionRationale(thisActivity,
                Permission)) {

        } else {
            ActivityCompat.requestPermissions(thisActivity,
                    new String[]{Permission},
                    Code);
        }
    }
}

public boolean CheckPermission(Activity context, String Permission) {
    if (ContextCompat.checkSelfPermission(context,
            Permission) == PackageManager.PERMISSION_GRANTED) {
        return true;
    } else {
        return false;
    }
}

在androidmainfest

 <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

Answer 3

请使用以下代码：

if(imgDecodableString.exists()){
Bitmap decodedBitmap = BitmapFactory.decodeFile(imgDecodableString);
Log.d(Constants.TAG, "decodedBitmap: " + decodedBitmap);}

希望它会有所帮助。

BitmapFactory解码返回null

3 个答案: