如何使用SharedPreferences存储图像？Android系统

Question

我下面的代码将一个图像从gallery放入我的ImageButton中，但当我离开应用程序或移动到另一个活动时，图像总是不会保存，第一个背景会再次出现。

-我的班级

   protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    //Adding the picture bit   

    imgButton = (ImageButton) findViewById(R.id.AddPic);
    imgButton.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent GaleryIntent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
            startActivityForResult(GaleryIntent, RESULT_LOAD_IMAGE);
        }
    });
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {
        Uri SelectedImage = data.getData();
        String[] FilePathColumn = {MediaStore.Images.Media.DATA };

        Cursor SelectedCursor = getContentResolver().query(SelectedImage, FilePathColumn, null, null, null);
        SelectedCursor.moveToFirst();

        int columnIndex = SelectedCursor.getColumnIndex(FilePathColumn[0]);
        String picturePath = SelectedCursor.getString(columnIndex);
        SelectedCursor.close();

      //  Drawable d = new BitmapDrawable(getResources(),BitmapFactory.decodeFile(picturePath)); 
       // btnOpenGalery .setImageBitmap(d);
        imgButton.setImageBitmap(BitmapFactory.decodeFile(picturePath));
        Toast.makeText(getApplicationContext(), picturePath, Toast.LENGTH_SHORT).show();

    }

}   

我的XML

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical" >

<ImageButton
    android:id="@+id/AddPic"
    android:layout_width="100dp"
    android:layout_height="100dp"
    android:layout_gravity="center"
    android:gravity="left"
    android:onClick="AddPic"
    android:background="@drawable/ic_launcher" />

</LinearLayout>

Answer 1

如果要使用sharedPreferences,请使用以下代码：

  SharedPreferences sharedPreferences;

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sharedPreferences = getSharedPreferences("data",  context.MODE_PRIVATE);

  //Adding the picture bit    

imgButton = (ImageButton) findViewById(R.id.AddPic);
imgButton.setOnClickListener(new OnClickListener() { 
    @Override 
    public void onClick(View v) {
        Intent GaleryIntent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
        startActivityForResult(GaleryIntent, RESULT_LOAD_IMAGE);
    } 
}); 

if(sharedPreferences!=null)
String path = sharedPreferences.getString("path", null);
if(path!=null)
  imgButton.setImageBitmap(BitmapFactory.decodeFile(path));




} 
@Override 
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

super.onActivityResult(requestCode, resultCode, data);
if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {
    Uri SelectedImage = data.getData();
    String[] FilePathColumn = {MediaStore.Images.Media.DATA };

    Cursor SelectedCursor = getContentResolver().query(SelectedImage, FilePathColumn, null, null, null);
    SelectedCursor.moveToFirst();

    int columnIndex = SelectedCursor.getColumnIndex(FilePathColumn[0]);
    String picturePath = SelectedCursor.getString(columnIndex);
    SelectedCursor.close();
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putString("path", picturePath);
    editor.commit();

  //  Drawable d = new BitmapDrawable(getResources(),BitmapFactory.decodeFile(picturePath));  
   // btnOpenGalery .setImageBitmap(d); 
    imgButton.setImageBitmap(BitmapFactory.decodeFile(picturePath));
    Toast.makeText(getApplicationContext(), picturePath, Toast.LENGTH_SHORT).show();

} 

}