Java讀取圖片縮略圖的bug

一定要在相冊查看下形成緩存

最近的一個連接服務端的應用，需要讀取圖片，一般供用戶發布商品選擇上傳圖片，初始的圖片列表應該是縮略圖，只有確定了，才上傳原圖，OK不多說上代碼

package edu.buaa.erhuo;
    
    
import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
    
    
import org.json.JSONArray;
import org.json.JSONObject;
    
    
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.app.AlertDialog.Builder;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import edu.buaa.erhuo.R;
import edu.buaa.erhuo.Utils.NetworkUtils;
    
    
public class PubActivity extends Activity {
private EditText et_title,et_des;
private Button btn_choose,btn_addSubmit;
private Spinner spinner_typeId;
private ArrayAdapter<String> adapter;
private List<String> allValues = new ArrayList<String>();
private List<Integer> allTypeIds = new ArrayList<Integer>();
private Handler handler;
private ImageView photoImg;
    
    
private String filePath;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_pub);
et_title=(EditText)findViewById(R.id.et_title);
et_des=(EditText)findViewById(R.id.et_description);
btn_choose=(Button)findViewById(R.id.btn_choose_photo);
btn_addSubmit=(Button)findViewById(R.id.btn_add_submit);
spinner_typeId=(Spinner)findViewById(R.id.spinner_type);
photoImg=(ImageView)findViewById(R.id.img_photo);
    
handler=new Handler(){
public void handleMessage(Message msg) {
if (msg.what==0) {//有網絡且讀取到數據
adapter=new ArrayAdapter<String>(PubActivity.this, android.R.layout.simple_spinner_item,allValues);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner_typeId.setAdapter(adapter);
}
else if (msg.what==1) {//提交到後台成功
Toast.makeText(PubActivity.this,"添加成功",Toast.LENGTH_SHORT).show();
et_title.setText("");
et_des.setText("");
spinner_typeId.setSelection(0);
photoImg.setImageURI(null);
filePath=null;
}
else if (msg.what==2) {
//提交到後台失敗
Toast.makeText(PubActivity.this,"添加失敗",Toast.LENGTH_SHORT).show();
}
}
};
// 調用工具類， 查詢所有的商品分類數據
Thread t=new Thread(){
public void run() {
try {
JSONArray array=NetworkUtils.getJSONArrayByUrl(NetworkUtils.GET_ALL_PRODUCT_TYPE_URL);
System.out.println(array+"kane...........");
// 循環查詢到的數據，保存到List集合裡
for (int i = 0; i < array.length(); i++) {
JSONObject obj = array.getJSONObject(i);
allValues.add(obj.getString("type_name"));
allTypeIds.add(obj.getInt("type_id"));
}
handler.sendEmptyMessage(0);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};
t.start();
    
btn_addSubmit.setOnClickListener(new OnClickListener() {
    
@Override
public void onClick(View arg0) {
final ProgressDialog dialog=new ProgressDialog(PubActivity.this);
dialog.setTitle("提示");
dialog.setMessage("正在提交數據.........");
dialog.show();
Thread t=new Thread(){
public void run() {
Map<String,String> params=new HashMap<String, String>();
params.put("product.product_name",et_title.getText().toString());
params.put("product.description",et_des.getText().toString());
params.put("product.type_id", allTypeIds.get(spinner_typeId.getSelectedItemPosition()).toString());
if (filePath==null) {
try {
String result=NetworkUtils.postDataByUrl(NetworkUtils.PRODUCT_INSERT_URL, params);
if (result.equals("ok")) {
handler.sendEmptyMessage(1);
}
else {
handler.sendEmptyMessage(2);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
handler.sendEmptyMessage(2);
}
    
}
else {
try {
String result = NetworkUtils.postFileByUrl(
NetworkUtils.PRODUCT_INSERT_URL, params,
filePath);
if (result.equals("ok")) {
handler.sendEmptyMessage(1);
} else {
handler.sendEmptyMessage(2);
}
} catch (Exception e) {
e.printStackTrace();
handler.sendEmptyMessage(2);
}
}
dialog.dismiss();
}
};
t.start();
    
}
});
    
btn_choose.setOnClickListener(new OnClickListener() {
    
@Override
public void onClick(View arg0) {
Builder builder=new Builder(PubActivity.this);
builder.setTitle("請選擇");
builder.setItems(new String[]{"拍照","從相冊選擇"}, new DialogInterface.OnClickListener() {
    
@Override
public void onClick(DialogInterface dialogInterface, int which) {
switch (which) {
case 0:
Intent intent=new Intent(PubActivity.this,CameraActivity.class);
startActivity(intent);
break;
    
    
case 1:
Intent in = new Intent(
PubActivity.this,
SelectImageActivity.class);
startActivityForResult(in, 1);
    
    
break;
}
}
});
builder.setPositiveButton("取消",new DialogInterface.OnClickListener() {
    
public void onClick(DialogInterface dialogInterface, int which) {
// TODO Auto-generated method stub
    
}
});
builder.create().show();
}
});
}
//請求的activity返回一個結果
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode == RESULT_OK) {
filePath = data.getStringExtra("filePath");
photoImg.setImageURI(Uri.fromFile(new File(filePath)));
}
}
    
}
    
package edu.buaa.erhuo;
    
    
import java.io.File;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
    
    
import edu.buaa.erhuo.adapter.PhotoImageAdapter;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.provider.MediaStore.Images;
import android.provider.MediaStore.Images.Media;
import android.provider.MediaStore.Images.Thumbnails;
import android.app.Activity;
import android.app.AlertDialog.Builder;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.content.Intent;
import android.database.Cursor;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ImageView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;
    
    
public class SelectImageActivity extends Activity {
private GridView gridView;
private PhotoImageAdapter adapter;
private List<Map<String, Object>> allValues=new ArrayList<Map<String,Object>>();
  @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_select_image);
gridView=(GridView)findViewById(R.id.grid);
//取得數據,Thumbnails縮略圖，必須先相冊查看形成緩存，不然沒有縮略圖
Cursor c=getContentResolver().query(MediaStore.Images.Thumbnails.EXTERNAL_CONTENT_URI, null,
null,null,null);
    
c.moveToFirst();
while (!c.isAfterLast()) {
Map<String,Object> map=new HashMap<String, Object>();
//對應原圖的ID
map.put("imageId",c.getLong(c.getColumnIndex(Thumbnails.IMAGE_ID)));
//DATA就是路徑名
map.put("filepath",c.getString(c.getColumnIndex(Thumbnails.DATA)));
    
allValues.add(map);
c.moveToNext();
}
c.close();
    
    
adapter=new PhotoImageAdapter(allValues, this);
gridView.setAdapter(adapter);
    
gridView.setOnItemClickListener(new OnItemClickListener() {
    
    
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int position,
long arg3) {
final Map<String,Object> map=allValues.get(position);
Builder builder=new Builder(SelectImageActivity.this);
builder.setTitle("確定使用這張好照片嗎？");
ImageView img=new ImageView(SelectImageActivity.this);
img.setImageURI(Uri.fromFile(new File(map.get("filepath").toString())));
builder.setView(img);
builder.setPositiveButton("確定", new OnClickListener() {
    
@Override
public void onClick(DialogInterface arg0, int arg1) {
//獲取圖片原始位置
//需要關聯查詢
Cursor c=getContentResolver().query(Images.Media.EXTERNAL_CONTENT_URI,null,Media._ID+"= ?", new String[]{map.get("imageId").toString()}, null);
String realPath=null;
if (c.moveToFirst()) {
realPath=c.getString(c.getColumnIndex(Media.DATA));
}
c.close();
Intent in=new Intent();
in.putExtra("filepath",realPath);
setResult(RESULT_OK,in);//給調用此activity的源頭發給回饋信息
finish();
}
});
builder.setNegativeButton("取消",new OnClickListener() {
    
@Override
public void onClick(DialogInterface arg0, int arg1) {
// TODO Auto-generated method stub
    
}
});
builder.create().show();
}
});
}
}

需要用到的adapter

package edu.buaa.erhuo.adapter;
    
    
import java.io.File;
import java.util.List;
import java.util.Map;
    
    
import android.content.Context;
import android.net.Uri;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView.LayoutParams;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import edu.buaa.erhuo.R;
import edu.buaa.erhuo.Utils.Globals;
    
    
public class PhotoImageAdapter extends BaseAdapter {
    
    
private List<Map<String, Object>> allValues;
private Context ctx;
    
    
public PhotoImageAdapter(List<Map<String, Object>> allValues, Context ctx) {
this.allValues = allValues;
this.ctx = ctx;
}
    
    
@Override
public int getCount() {
return allValues.size();
}
    
    
@Override
public Object getItem(int position) {
return allValues.get(position);
}
    
    
@Override
public long getItemId(int position) {
return position;
}
    
    
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = LayoutInflater.from(ctx).inflate(
R.layout.grid_image_line, null);
convertView.setLayoutParams(new LayoutParams(
LayoutParams.MATCH_PARENT, Globals.SCREEN_HEIGHT / 6));
}
    
    
Map<String, Object> map = allValues.get(position);
    
    
ImageView img = (ImageView) convertView
.findViewById(R.id.photo_img_line);
    
    
img.setImageURI(Uri.fromFile(new File(map.get("filePath").toString())));
    
    
return convertView;
}
    
    
}