Question

在我的应用中，用户通过点击指向他们的图库的按钮来选择图片。他们选择了图片但是一旦我退出应用程序，图片已经消失了。我怎么能保存它？如何使用SharedPeferences保存它？

import android.support.v7.app.ActionBarActivity;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;    
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.preference.PreferenceManager;




public class MyNewScreen extends ActionBarActivity {



 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.my_new_screen);



        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
            String picturePath = prefs.getString("profilePic", "");
            if(!picturePath.equals("")){
                  ImageView imageView = (ImageView) findViewById(R.id.imageView1);
                  imageView.setImageBitmap(BitmapFactory.decodeFile(picturePath));



            }


Button buttonLoadImage = (Button) findViewById(R.id.button1);


        buttonLoadImage.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View arg0) {

                Intent i = new Intent(
                        Intent.ACTION_PICK,
                        android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

                startActivityForResult(i, RESULT_LOAD_IMAGE);


            }
        });

 }


        private static int RESULT_LOAD_IMAGE = 1;

        @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 cursor = getContentResolver().query(selectedImage,
                        filePathColumn, null, null, null);
                cursor.moveToFirst();

                int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
                String picturePath = cursor.getString(columnIndex);
                cursor.close();

                ImageView imageView = (ImageView) findViewById(R.id.imageView1);
                imageView.setImageBitmap(BitmapFactory.decodeFile(picturePath));



                SharedPreferences shre = PreferenceManager.getDefaultSharedPreferences(this);
                Editor edit=shre.edit();
                edit.putString("profilePic", picturePath);
                edit.commit();

                    }
                }


        }

Answer 1

试试这些：其中prefs是你的sharedpreferences对象而不是布尔值，你传给他一个字符串有值

private void savePreferences(String key, boolean value) {
        prefs = PreferenceManager.getDefaultSharedPreferences(this);
        Editor editor = prefs.edit();
        editor.putBoolean(key, value);
        editor.commit();
    }

    private boolean loadSavedPreferences() {
        prefs = PreferenceManager.getDefaultSharedPreferences(this);
        return prefs.getBoolean("hasDataToSync", false);
    }

Answer 2

您正在从首选项中检索路径，但不保存任何内容。当你使用startActivityForResult时，我猜你会在onActivityResult中找到路径，那里你应该这样做：

prefs = getPreferences(Context.MODE_PRIVATE);
Editor editor = prefs.edit();
editor.putSring(KEY, path);
editor.commit();

当用户启动应用时，在onCreate中检索刚刚存储的路径：

String path = prefs.getString(KEY, "");
if (path != ""){
   ImageView imageView = (ImageView) findViewById(R.id.imageView1);
   imageView.setImageBitmap(BitmapFactory.decodeFile(path));
}

Answer 3

您的代码在我的设备上正常运行。我唯一需要补充的是：

BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 6;
options.inScaled = false;
options.inPreferredConfig = Bitmap.Config.ARGB_8888;
imageView.setImageBitmap(BitmapFactory.decodeFile(picturePath, options));

如果图像大到足以抛出OutOfMemory异常。如果您使用模拟器，它可能不起作用。

如何在Android应用程序的SharedPreferences中保存图像路径？我的代码不工作

3 个答案: