在 onCreate 中加载图像无法正确填充适配器
Loading image in onCreate doesn't fill adapter correctly
我的应用程序能够拍照、保存并在列表中显示它们。它们也可以被删除并且列表被正确更新。
但是,如果我关闭应用程序然后再次启动它,列表将不再正确。详细:
这些是我拍摄两张照片后适配器中的列表元素:
List[0] 20150603_042556
List[1] 20150603_042601
这些图片保存正确。但是,如果我关闭并再次打开该应用程序,则会发生以下情况:
Loaded selfie:﹕ 20150603_042556
List[0] 20150603_042556
Loaded selfie: 20150603_042601
List[0] 20150603_042601
List[1] 20150603_042601
这是添加函数:
public void add(SelfieRecord listItem) {
list.add(listItem);
for(int k=0;k<list.size();k++)
Log.i("List: ", String.valueOf(k) + " " + list.get(k).getPicName());
notifyDataSetChanged();
}
这是我加载保存图片的方式:
for (int ii = 0; ii < dirFiles.length; ii++) {
File file = dirFiles[ii];
String path = file.getAbsolutePath();
selfie.setPic(path);
selfie.setPicName(path.substring(path.indexOf("_") + 1, path.lastIndexOf("_")));
Log.i(TAG+" Loaded selfie: ",path);
mAdapter.add(selfie);
}
想不通发生了什么。
编辑:更多代码如下。
主要activity:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// setup notifications
setNotifications();
mListView = (ListView)findViewById(R.id.selfieList);
mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Intent intent = new Intent(MainActivity.this, ViewActivity.class);
SelfieRecord record = (SelfieRecord) mAdapter.getItem(position);
intent.putExtra(SELFIE_KEY, record.getPic());
startActivity(intent);
}
});
mAdapter = new SelfieAdapter(getApplicationContext());
mListView.setAdapter(mAdapter);
// load selfies
if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState()) && mAdapter.getCount()==0) {
// gets the files in the directory
File fileDirectory = new File(getExternalFilesDir(Environment.DIRECTORY_PICTURES).getAbsolutePath());
if (!fileDirectory.exists()) {
fileDirectory.mkdirs();
}
// lists all the files into an array
File[] dirFiles = fileDirectory.listFiles();
if (dirFiles.length != 0) {
SelfieRecord selfie = new SelfieRecord();
// loops through the array of files, outputing the name to console
for (int ii = 0; ii < dirFiles.length; ii++) {
File file = dirFiles[ii];
String path = file.getAbsolutePath();
selfie.setPic(path);
selfie.setPicName(path.substring(path.indexOf("_") + 1, path.lastIndexOf("_")));
Log.i(TAG+" Loaded selfie: ",path);
mAdapter.add(selfie);
}
}
}
registerForContextMenu(mListView);
}
在适配器中:
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View newView = convertView;
ViewHolder holder;
SelfieRecord curr = list.get(position);
Log.i("List: ", String.valueOf(position)+" "+list.get(position).getPicName());
if (null == convertView) {
holder = new ViewHolder();
newView = inflater.inflate(R.layout.list_record, parent, false);
holder.pic = (ImageView) newView.findViewById(R.id.pic);
holder.name = (TextView) newView.findViewById(R.id.pic_name);
newView.setTag(holder);
} else {
holder = (ViewHolder) newView.getTag();
}
//setPic(holder.pic, curr.getPic());
holder.name.setText(curr.getPicName());
mImageView = holder.pic;
new BitmapLoader().execute(curr.getPic());
Log.i("Loader: ", String.valueOf(position) + " " + curr.getPicName());
return newView;
}
static class ViewHolder {
ImageView pic;
TextView name;
}
public void add(SelfieRecord listItem) {
list.add(listItem);
for(int k=0;k<list.size();k++)
Log.i("List: ", String.valueOf(k) + " " + list.get(k).getPicName());
notifyDataSetChanged();
}
public void remove(int position) {
list.remove(position);
notifyDataSetChanged();
}
位图加载器:
public class BitmapLoader extends AsyncTask<String,Integer,Bitmap> {
@Override
protected Bitmap doInBackground(String... resId) {
// Get the dimensions of the View
int targetW = Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 160, mContext.getResources().getDisplayMetrics()));
int targetH = Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 120, mContext.getResources().getDisplayMetrics()));
// Get the dimensions of the bitmap
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
bmOptions.inJustDecodeBounds = true;
BitmapFactory.decodeFile(resId[0], bmOptions);
int photoW = bmOptions.outWidth;
int photoH = bmOptions.outHeight;
// Determine how much to scale down the image
int scaleFactor = Math.min(photoW/targetW, photoH/targetH);
// Decode the image file into a Bitmap sized to fill the View
bmOptions.inJustDecodeBounds = false;
bmOptions.inSampleSize = scaleFactor;
bmOptions.inPurgeable = true;
Bitmap bitmap = BitmapFactory.decodeFile(resId[0], bmOptions);
return bitmap;
}
@Override
protected void onPostExecute(Bitmap result) {
mImageView.setImageBitmap(result);
}
}
我认为问题出在我将元素从存储中恢复后放入适配器时:
Loaded selfie:﹕ 20150603_042556
List[0] 20150603_042556
Loaded selfie: 20150603_042601
List[0] 20150603_042601
List[1] 20150603_042601
第二次调用适配器的添加方法覆盖第一个元素。为什么?
通过更改创建时的 for 循环解决:
if (dirFiles.length != 0) {
// loops through the array of files, outputing the name to console
for (int ii = 0; ii < dirFiles.length; ii++) {
File file = dirFiles[ii];
String path = file.getAbsolutePath();
SelfieRecord selfie = new SelfieRecord();
selfie.setPic(path);
selfie.setPicName(path.substring(path.indexOf("_") + 1, path.lastIndexOf("_")));
Log.i(TAG+" Loaded selfie: ",path);
mAdapter.add(selfie);
}
}
必须将不同的 SelfieRecord 对象传递给添加方法。
我的应用程序能够拍照、保存并在列表中显示它们。它们也可以被删除并且列表被正确更新。 但是,如果我关闭应用程序然后再次启动它,列表将不再正确。详细:
这些是我拍摄两张照片后适配器中的列表元素:
List[0] 20150603_042556
List[1] 20150603_042601
这些图片保存正确。但是,如果我关闭并再次打开该应用程序,则会发生以下情况:
Loaded selfie:﹕ 20150603_042556
List[0] 20150603_042556
Loaded selfie: 20150603_042601
List[0] 20150603_042601
List[1] 20150603_042601
这是添加函数:
public void add(SelfieRecord listItem) {
list.add(listItem);
for(int k=0;k<list.size();k++)
Log.i("List: ", String.valueOf(k) + " " + list.get(k).getPicName());
notifyDataSetChanged();
}
这是我加载保存图片的方式:
for (int ii = 0; ii < dirFiles.length; ii++) {
File file = dirFiles[ii];
String path = file.getAbsolutePath();
selfie.setPic(path);
selfie.setPicName(path.substring(path.indexOf("_") + 1, path.lastIndexOf("_")));
Log.i(TAG+" Loaded selfie: ",path);
mAdapter.add(selfie);
}
想不通发生了什么。
编辑:更多代码如下。
主要activity:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// setup notifications
setNotifications();
mListView = (ListView)findViewById(R.id.selfieList);
mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Intent intent = new Intent(MainActivity.this, ViewActivity.class);
SelfieRecord record = (SelfieRecord) mAdapter.getItem(position);
intent.putExtra(SELFIE_KEY, record.getPic());
startActivity(intent);
}
});
mAdapter = new SelfieAdapter(getApplicationContext());
mListView.setAdapter(mAdapter);
// load selfies
if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState()) && mAdapter.getCount()==0) {
// gets the files in the directory
File fileDirectory = new File(getExternalFilesDir(Environment.DIRECTORY_PICTURES).getAbsolutePath());
if (!fileDirectory.exists()) {
fileDirectory.mkdirs();
}
// lists all the files into an array
File[] dirFiles = fileDirectory.listFiles();
if (dirFiles.length != 0) {
SelfieRecord selfie = new SelfieRecord();
// loops through the array of files, outputing the name to console
for (int ii = 0; ii < dirFiles.length; ii++) {
File file = dirFiles[ii];
String path = file.getAbsolutePath();
selfie.setPic(path);
selfie.setPicName(path.substring(path.indexOf("_") + 1, path.lastIndexOf("_")));
Log.i(TAG+" Loaded selfie: ",path);
mAdapter.add(selfie);
}
}
}
registerForContextMenu(mListView);
}
在适配器中:
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View newView = convertView;
ViewHolder holder;
SelfieRecord curr = list.get(position);
Log.i("List: ", String.valueOf(position)+" "+list.get(position).getPicName());
if (null == convertView) {
holder = new ViewHolder();
newView = inflater.inflate(R.layout.list_record, parent, false);
holder.pic = (ImageView) newView.findViewById(R.id.pic);
holder.name = (TextView) newView.findViewById(R.id.pic_name);
newView.setTag(holder);
} else {
holder = (ViewHolder) newView.getTag();
}
//setPic(holder.pic, curr.getPic());
holder.name.setText(curr.getPicName());
mImageView = holder.pic;
new BitmapLoader().execute(curr.getPic());
Log.i("Loader: ", String.valueOf(position) + " " + curr.getPicName());
return newView;
}
static class ViewHolder {
ImageView pic;
TextView name;
}
public void add(SelfieRecord listItem) {
list.add(listItem);
for(int k=0;k<list.size();k++)
Log.i("List: ", String.valueOf(k) + " " + list.get(k).getPicName());
notifyDataSetChanged();
}
public void remove(int position) {
list.remove(position);
notifyDataSetChanged();
}
位图加载器:
public class BitmapLoader extends AsyncTask<String,Integer,Bitmap> {
@Override
protected Bitmap doInBackground(String... resId) {
// Get the dimensions of the View
int targetW = Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 160, mContext.getResources().getDisplayMetrics()));
int targetH = Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 120, mContext.getResources().getDisplayMetrics()));
// Get the dimensions of the bitmap
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
bmOptions.inJustDecodeBounds = true;
BitmapFactory.decodeFile(resId[0], bmOptions);
int photoW = bmOptions.outWidth;
int photoH = bmOptions.outHeight;
// Determine how much to scale down the image
int scaleFactor = Math.min(photoW/targetW, photoH/targetH);
// Decode the image file into a Bitmap sized to fill the View
bmOptions.inJustDecodeBounds = false;
bmOptions.inSampleSize = scaleFactor;
bmOptions.inPurgeable = true;
Bitmap bitmap = BitmapFactory.decodeFile(resId[0], bmOptions);
return bitmap;
}
@Override
protected void onPostExecute(Bitmap result) {
mImageView.setImageBitmap(result);
}
}
我认为问题出在我将元素从存储中恢复后放入适配器时:
Loaded selfie:﹕ 20150603_042556
List[0] 20150603_042556
Loaded selfie: 20150603_042601
List[0] 20150603_042601
List[1] 20150603_042601
第二次调用适配器的添加方法覆盖第一个元素。为什么?
通过更改创建时的 for 循环解决:
if (dirFiles.length != 0) {
// loops through the array of files, outputing the name to console
for (int ii = 0; ii < dirFiles.length; ii++) {
File file = dirFiles[ii];
String path = file.getAbsolutePath();
SelfieRecord selfie = new SelfieRecord();
selfie.setPic(path);
selfie.setPicName(path.substring(path.indexOf("_") + 1, path.lastIndexOf("_")));
Log.i(TAG+" Loaded selfie: ",path);
mAdapter.add(selfie);
}
}
必须将不同的 SelfieRecord 对象传递给添加方法。