如何在Android中使用SharedPreference存储图像?

问题描述

我想使用SharedPreference将图像保存在android中.我有两个活动类，当我单击第一个活动的按钮时，它将调用第二个活动，第二个活动在列表视图中显示我的首选名称，并且还将android墙纸重置为我设置为首选墙纸的图像在第一个活动中.

I want to save images in android using SharedPreference. I have two activity classes, when I click the button of the first activity it will call the second activity and the second activity displays my preferred name in a list view and also resets the android wallpaper to the image that I had set as a preferred wallpaper in the first activity.

第二个活动的代码是:

public class PreferencesActivityTest extends PreferenceActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);


            SharedPreferences myPrefs = this.getSharedPreferences("myPrefs", MODE_WORLD_READABLE);
            String prefName = myPrefs.getString("PREF_USERNAME", "nothing");
            String wallPaper = myPrefs.getString("PREFS_NAME", null);


            if(wallPaper != null) {

                try {

                      Bitmap bm = BitmapFactory.decodeFile("/data/misc/wallpaper/"+wallPaper);
                      Log.d(getClass().getSimpleName(),"Wallpaper name is: "+ wallPaper);
                      setWallpaper(bm);
                      Toast.makeText(this, "Wall paper has been changed." +
                                  "You may go to the home screen to view the same", Toast.LENGTH_LONG).show();
                }

                catch (FileNotFoundException fe){
                      Log.e(getClass().getSimpleName(),"File not found");
                } catch (IOException ie) {
                      Log.e(getClass().getSimpleName()," IO Exception");
                }

    }


        ArrayList<String> results = new ArrayList<String>();
        results.add("Your Preferred name is: " + prefName);
      this.setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,results));
    }

第一个活动调用第二个活动，但没有调用if(wallPaper != null){}

The first activity calls the second activity but it is not calling if(wallPaper != null){}

为什么不起作用?

推荐答案

不建议将图像存储在共享"首选项中，您应该将该图像存储到sdcard.然后将图像路径(来自sdcard)存储到共享"首选项中，如下所示: -

Its not recommended to store image in Share preferences And you should store that image to sdcard.And then store image path (from sdcard) into Share preferences like this--

    SharedPreferences shre = PreferenceManager.getDefaultSharedPreferences(this);
    Editor edit=shre.edit();
    edit.putString("imagepath","/sdcard/imh.jpeg");
    edit.commit();

，然后使用此路径从sdcard获取图像

and then fetch image from sdcard by using this path

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