英文:
How to save and restore bitmap before close app
问题
我想为应用的用户制作可替换的个人背景。当他们更换图片时，我无法在关闭应用之前保存它。我尝试过使用共享首选项，但对于位图无效。在关闭应用之前如何保存和恢复位图？
英文:
I wanna make replaceable personal background for app's users. When they change picture I can't save it before close app. I try shared preferences but not working for bitmap. How can I save and restore bitmap before close app?
答案1
得分: 1
// 使用这个方法来保存位图，在你有位图时调用此方法
private void saveBitmap(Bitmap pBitmap) {
ContextWrapper contextWrapper = new ContextWrapper(getApplicationContext());
File directory = contextWrapper.getDir("folderName", Context.MODE_PRIVATE);
if (!directory.exists()) {
directory.mkdirs();
}
File file = new File(directory, "fileName.png");
FileOutputStream fos = null;
try {
fos = new FileOutputStream(file);
pBitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
fos.close();
String filePath = file.getAbsolutePath();
// 在将来使用时，将这个路径保存在共享偏好中。
} catch (Exception e) {
Log.e("SAVE_IMAGE", e.getMessage(), e);
}
}
// 使用这个方法从文件路径获取位图（你之前保存的）
private void getBitmapFromPath(String pFilePath) {
try {
File f = new File(pFilePath);
Bitmap bitmap = BitmapFactory.decodeStream(new FileInputStream(f));
// 根据需要使用这个位图
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
// 用于保存和检索文件路径的部分
// 保存文件路径的部分
PreferenceManager.getDefaultSharedPreferences(context).edit().putString("FILE_PATH_KEY", filePath).apply();
// 获取已保存的文件路径的部分
String filePath = PreferenceManager.getDefaultSharedPreferences(context).getString("FILE_PATH_KEY", "未成功检索到路径！");
英文:
//use this method to save your bitmap, call this method when you have bitmap
private void saveBitmap(Bitmap pBitmap){
ContextWrapper contextWrapper = new ContextWrapper(getApplicationContext());
File directory = contextWrapper.getDir("folderName", Context.MODE_PRIVATE);
if (!directory.exists()) {
directory.mkdirs();
}
File file = new File(directory, "fileName.png");
FileOutputStream fos = null;
try {
fos = new FileOutputStream(file);
pBitmap.compress(Bitmap.CompressFormat.PNG, 100, fos);
fos.close();
String filePath = file.getAbsolutePath();
//save this path in shared preference to use in future.
} catch (Exception e) {
Log.e("SAVE_IMAGE", e.getMessage(), e);
}
}
use this method to get bitmap from file path that you saved
private void getBitmapFromPath(String pFilePath) {
try {
File f = new File(pFilePath);
Bitmap bitmap = BitmapFactory.decodeStream(new FileInputStream(f));
//use this bitmap as you want
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
for saving and retrieving file path
//This for saving file path
PreferenceManager.getDefaultSharedPreferences(context).edit().putString("FILE_PATH_KEY", filePath).apply();
//this for getting saved file path
String filePath = PreferenceManager.getDefaultSharedPreferences(context).getString("FILE_PATH_KEY", "path not retrieved successfully!");
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