我正在尝试将电池信息记录到csv文件中，现在我只是在每次BroadcastReceiver收到意图后尝试记录。这是一个片段：
public class MainActivity extends Activity
private static final String TAG = "MainActivity";
double voltage;
float temperature;
int soc;
Float current;
CSVWriter writer = null;
File dir = new File(Environment.getExternalStorageDirectory() + "/BatteryApp");
FileWriter fw;
File f;
boolean fexists;
@Override
protected void onCreate(Bundle savedInstanceState) {
Log.w(TAG, "App created");
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
this.registerReceiver(this.batteryInfoReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
if (!dir.exists())
{
dir.mkdirs();
}
int a = 1;
fexists = true;
while(fexists) {
File newFilename = new File(dir + "/battery" + Integer.toString(a) + ".csv");
if (newFilename.exists()) {
a++;
} else {
f = newFilename;
MediaScannerConnection.scanFile(MainActivity.this, new String[]{f.toString()}, null,
new MediaScannerConnection.OnScanCompletedListener() {
public void onScanCompleted(String path, Uri uri) {
Log.i("External Storage", "Scanned" + dir + ":");
Log.i("External Storage", "-> uri=" + uri);
}
});
try {
writer = new CSVWriter(new FileWriter(f, true), ',');
String[] entries = "Voltage(V),Temperature(C),SOC(%),Current(Ah),".split(",");
writer.writeNext(entries);
writer.flush();
writer.close();
}
catch (IOException ioex) {
ioex.printStackTrace();
}
fexists = false;
}
}
text = (TextView) findViewById(R.id.textView)
}
private BroadcastReceiver batteryInfoReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
Log.w(TAG, "Broadcast Receiver received");
//After receiving battery info from BatteryManager
text.setText(
voltage + " V\n"
+ temperature + " C\n"
+ current + " Ah\n"
+ soc + " %\n");
text.addTextChangedListener(new TextWatcher() {
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
Log.v(TAG, "Voltage(V): " + voltageText + " Temp(C): " + temperatureText + " SOC(%): " + socText + " Current(A): " + currentText );
try
{
writer = new CSVWriter(new FileWriter(f, true), ',');
String [] data = (voltageText + "," + temperatureText + "," + socText + "," + currentText + ",").split(",");
writer.writeNext(data);
writer.flush();
writer.close();
MediaScannerConnection.scanFile(MainActivity.this, new String[]{f.toString()}, null,
new MediaScannerConnection.OnScanCompletedListener() {
public void onScanCompleted(String path, Uri uri) {
Log.i("External Storage", "Scanned" + dir + ":");
Log.i("External Storage", "-> uri=" + uri);
}
});
}
catch(IOException ioex)
{
ioex.printStackTrace();
}
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
@Override
public void afterTextChanged(Editable s) {}
});
}
};
问题：如下面的logcat日志所示，在onReceive（）的每次迭代之后，检索到的信息比以前显示的更多。此外，在拔出并插回USB之后，csv上的数据才会更新/无法看到。
D/OpenGLRenderer﹕ Enabling debug mode 0
I/External Storage﹕ Scanned/storage/emulated/0/BatteryApp:
I/External Storage﹕ -> uri=content://media/external/file/550
W/MainActivity﹕ Broadcast Receiver received
V/MainActivity﹕ Voltage(V): 4.236 Temp(C): 33.0 SOC(%): 84 Current(A): 0.048
I/External Storage﹕ Scanned/storage/emulated/0/BatteryApp:
I/External Storage﹕ -> uri=content://media/external/file/550
D/dalvikvm﹕ Debugger has detached; object registry had 1 entries
W/MainActivity﹕ Broadcast Receiver received
V/MainActivity﹕ Voltage(V): 4.248 Temp(C): 33.0 SOC(%): 84 Current(A): 0.054
V/MainActivity﹕ Voltage(V): 4.248 Temp(C): 33.0 SOC(%): 84 Current(A): 0.054
I/External Storage﹕ Scanned/storage/emulated/0/BatteryApp:
I/External Storage﹕ -> uri=content://media/external/file/550
I/External Storage﹕ Scanned/storage/emulated/0/BatteryApp:
I/External Storage﹕ -> uri=content://media/external/file/550
W/MainActivity﹕ Broadcast Receiver received
V/MainActivity﹕ Voltage(V): 4.249 Temp(C): 33.0 SOC(%): 84 Current(A): 0.08
V/MainActivity﹕ Voltage(V): 4.249 Temp(C): 33.0 SOC(%): 84 Current(A): 0.08
V/MainActivity﹕ Voltage(V): 4.249 Temp(C): 33.0 SOC(%): 84 Current(A): 0.08
I/External Storage﹕ Scanned/storage/emulated/0/BatteryApp:
I/External Storage﹕ -> uri=content://media/external/file/550
I/External Storage﹕ Scanned/storage/emulated/0/BatteryApp:
I/External Storage﹕ -> uri=content://media/external/file/550
I/External Storage﹕ Scanned/storage/emulated/0/BatteryApp:
I/External Storage﹕ -> uri=content://media/external/file/550
W/MainActivity﹕ Broadcast Receiver received
V/MainActivity﹕ Voltage(V): 4.247 Temp(C): 33.0 SOC(%): 85 Current(A): 0.029
V/MainActivity﹕ Voltage(V): 4.247 Temp(C): 33.0 SOC(%): 85 Current(A): 0.029
V/MainActivity﹕ Voltage(V): 4.247 Temp(C): 33.0 SOC(%): 85 Current(A): 0.029
V/MainActivity﹕ Voltage(V): 4.247 Temp(C): 33.0 SOC(%): 85 Current(A): 0.029
I/External Storage﹕ Scanned/storage/emulated/0/BatteryApp:
I/External Storage﹕ -> uri=content://media/external/file/550
I/External Storage﹕ Scanned/storage/emulated/0/BatteryApp:
I/External Storage﹕ -> uri=content://media/external/file/550
I/External Storage﹕ Scanned/storage/emulated/0/BatteryApp:
I/External Storage﹕ -> uri=content://media/external/file/550
I/External Storage﹕ Scanned/storage/emulated/0/BatteryApp:
I/External Storage﹕ -> uri=content://media/external/file/550
任何关于为什么会发生这种情况的想法以及解决方案（如果有的话）都将非常感激。
答案 0 :(得分：1)
从您的代码中可以清楚地看出来。消息正在TextWatcher侦听器中记录，每次调用onReceive方法时，都会附加另一个侦听器。每次收到广播时都不应该重新创建监听器，而应该只创建一次。
此外，似乎直接生成响应广播的日志消息要简单得多，而不是更新UI元素然后触发另一个事件来响应。