我有一个功能loadPresetClicked(View v)。在一个示例中，它通过单击按钮调用，但我想在没有按钮的情况下调用它loadPresetClicked()。
public void loadPresetClicked() {
String[] names = new String[10 + model.getPresets().size()];
for (int i = 0; i < 10; i++) {
names[i] = eqService.equalizer().getPresetName((short) i);
}
for (short i = 0; i < model.getPresets().size(); i++) {
names[i + 10] = model.getPresets().get(i).getName();
}
this.onSaveInstanceState(new Bundle());
}
均衡器型号：
public class EqualizerModel extends Observable {
private ArrayList<Preset> presets;
private Scanner inStream;
private PrintWriter outStream;
private EqualizerActivity parent;
private short[] bandLevels;
public EqualizerModel(EqualizerActivity parent) {
presets = new ArrayList<Preset>();
this.parent = parent;
bandLevels = new short[5];
}
public void writePresetFile() {
File directory = new File("/sdcard/Aurem/");
directory.mkdirs();
File outputFile = new File(directory, "presets.txt");
FileOutputStream outputStream;
String output = "";
try {
outputStream = new FileOutputStream(outputFile);
outStream = new PrintWriter(outputStream);
} catch (IOException e) {
System.out.println(e.getMessage());
}
for (int i = 0; i < presets.size(); i++) {
short index = (short) i;
Preset preset = presets.get(index);
output += preset.index() + ",";
short[] bands = preset.getBands();
for (int j = 0; j < 5; j++) {
output += bands[j] + ",";
}
output += preset.getName() + "\n";
}
outStream.print(output);
outStream.close();
}
public void writeLastStateFile() {
File directory = new File("/sdcard/Aurem/");
directory.mkdirs();
File outputFile = new File(directory, "lastState.txt");
FileOutputStream outputStream;
String output = "";
try {
outputStream = new FileOutputStream(outputFile);
outStream = new PrintWriter(outputStream);
} catch (IOException e) {
System.out.println(e.getMessage());
}
for (short i = 0; i < bandLevels.length; i++) {
output += bandLevels[i] + "\n";
}
outStream.print(output);
outStream.close();
}
public void readLastStateFile() {
FileInputStream inputStream;
try {
inputStream = new FileInputStream("/sdcard/Aurem/lastState.txt");
inStream = new Scanner(inputStream);
} catch (IOException e) {
System.out.println(e.getMessage());
}
inStream.useDelimiter("\n");
for (short i = 0; i < 5; i++) {
bandLevels[i] = Short.parseShort(inStream.nextLine());
}
inStream.close();
}
public void readPresetFile() {
FileInputStream inputStream;
try {
inputStream = new FileInputStream("/sdcard/Aurem/presets.txt");
inStream = new Scanner(inputStream);
} catch (IOException e) {
System.out.println(e.getMessage());
}
inStream.useDelimiter("\n");
while (inStream.hasNext()) {
String line = inStream.next();
String[] data = line.split(",");
short index = Short.parseShort(data[0]);
short[] bands = new short[5];
Preset preset = new Preset(index, data[6]);
for (int i = 1; i < 6; i++) {
bands[i - 1] = Short.parseShort(data[i]);
}
preset.setBands(bands);
for (int i = 0; i < presets.size(); i++)
Log.d("Preset", presets.get(i) + "");
presets.add(index, preset);
}
inStream.close();
}
public Preset getPreset(short index) {
return presets.get(index);
}
public void setBandLevel(short index, short bandLevel) {
bandLevels[index] = bandLevel;
setChanged();
notifyObservers();
}
public short getBandLevel(short index) {
if (index < 0 || index >= bandLevels.length) {
return 0;
}
return bandLevels[index];
}
public void createPreset(String name, short[] bands) {
int index = presets.size();
Preset preset = new Preset((short) (index), name);
preset.setBands(bands);
presets.add(preset);
}
public ArrayList<Preset> getPresets() {
return presets;
}
}
均衡器服务：
public class EqualizerService extends Service {
private final ServiceBinder binder = new ServiceBinder();
private Equalizer eq;
@Override
public void onCreate() {
super.onCreate();
eq = new Equalizer(1000000, 0);
for (short i = 0; i < 5; i++) {
eq.setBandLevel(i, (short) 0);
}
eq.setEnabled(true);
}
public int onStartCommand(Intent intent, int flags, int startId) {
super.onStartCommand(intent, flags, startId);
return START_STICKY;
}
@Override
public IBinder onBind(Intent arg0) {
return binder;
}
@Override
public void onDestroy() {
super.onDestroy();
}
public String testPrintout() {
String output = eq.getProperties().toString() + "\n";
for (short i = 0; i < 5; i++) {
output += eq.getBandLevel(i) + " ";
}
output += "\n";
short band = 1;
short level = 300;
eq.setBandLevel(band, level);
for (short i = 0; i < 5; i++) {
output += eq.getBandLevel(i) + " ";
}
output += "\n\n";
for (short i = 0; i < 10; i++) {
output += i + " " + eq.getPresetName(i) + "\n";
}
short[] range = eq.getBandLevelRange();
output += "\n" + "Level Range: " + range[0] + " to " + range[1] + "\n";
output += "\nThe Center Frequencies of each band\n";
for (short i = 0; i < 5; i++) {
output += i + " " + eq.getCenterFreq(i) + "\n";
}
return "THIS IS A TEST!!!\n\n" + output;
}
public Equalizer equalizer() {
return eq;
}
public class ServiceBinder extends Binder {
EqualizerService getService() {
return EqualizerService.this;
}
}
}
在主要活动中，我开始服务并调用loadPresetClicked()，但它抛出NullPointerException
model = new EqualizerModel(this);
initUI();
File file = new File("/sdcard/Aurem/presets.txt");
if (!file.exists()) {
model.writePresetFile();
}
model.readPresetFile();
file = new File("/sdcard/Aurem/lastState.txt");
if (!file.exists()) {
for (short i = 0; i < 5; i++) {
model.setBandLevel(i, (short) 0);
}
} else {
model.readLastStateFile();
}
intent = new Intent(this, EqualizerService.class);
startService(intent);
bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE);
isServiceOn = true;
loadPresetClicked();
添加 LogCat 输出：
06-04 11:11:30.828: E/AndroidRuntime(16106): FATAL EXCEPTION: main
06-04 11:11:30.828: E/AndroidRuntime(16106): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.musicplayer.app/com.musicplayer.eq.EqualizerActivity}: java.lang.NullPointerException
06-04 11:11:30.828: E/AndroidRuntime(16106): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2355)
06-04 11:11:30.828: E/AndroidRuntime(16106): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2391)
06-04 11:11:30.828: E/AndroidRuntime(16106): at android.app.ActivityThread.access$600(ActivityThread.java:151)
06-04 11:11:30.828: E/AndroidRuntime(16106): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1335)
06-04 11:11:30.828: E/AndroidRuntime(16106): at android.os.Handler.dispatchMessage(Handler.java:99)
06-04 11:11:30.828: E/AndroidRuntime(16106): at android.os.Looper.loop(Looper.java:155)
06-04 11:11:30.828: E/AndroidRuntime(16106): at android.app.ActivityThread.main(ActivityThread.java:5493)
06-04 11:11:30.828: E/AndroidRuntime(16106): at java.lang.reflect.Method.invokeNative(Native Method)
06-04 11:11:30.828: E/AndroidRuntime(16106): at java.lang.reflect.Method.invoke(Method.java:511)
06-04 11:11:30.828: E/AndroidRuntime(16106): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1028)
06-04 11:11:30.828: E/AndroidRuntime(16106): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:795)
06-04 11:11:30.828: E/AndroidRuntime(16106): at dalvik.system.NativeStart.main(Native Method)
06-04 11:11:30.828: E/AndroidRuntime(16106): Caused by: java.lang.NullPointerException
06-04 11:11:30.828: E/AndroidRuntime(16106): at com.musicplayer.eq.EqualizerActivity.loadPresetClicked(EqualizerActivity.java:225)
06-04 11:11:30.828: E/AndroidRuntime(16106): at com.musicplayer.eq.EqualizerActivity.onCreate(EqualizerActivity.java:88)
06-04 11:11:30.828: E/AndroidRuntime(16106): at android.app.Activity.performCreate(Activity.java:5066)
06-04 11:11:30.828: E/AndroidRuntime(16106): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1101)
06-04 11:11:30.828: E/AndroidRuntime(16106): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2311)
06-04 11:11:30.828: E/AndroidRuntime(16106): ... 11 more