我正在制作一个简单的秒表应用程序。但是在手机上打开时会崩溃。当单独作为一个简单的Java应用程序运行时，Java代码工作正常。但是，在使用start，pause和reset按钮在Android中实现此java代码时，它无法正常工作..
这是代码......
public class MainActivity extends AppCompatActivity {
private boolean running;
private int second;
private TextView display;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
running = false;
second = 0;
Button start_button = (Button)findViewById(R.id.start);
Button pause_button = (Button)findViewById(R.id.pause);
Button reset_button = (Button)findViewById(R.id.reset);
display = (TextView)findViewById(R.id.textView2);
start_button.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View v){
running = true;
startTimer();
}
});
pause_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
running = false;
startTimer();
}
});
reset_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
running = false;
second = 0;
display.setText("");
display.setHint("00:00:00");
}
});
}
protected void startTimer(){
int hours;
int minute;
int second_hand;
while (running){
second++;
hours = second/3600;
minute = (second%3600)/60;
second_hand = second%60;
String time = String.format("%02d:%02d;%02d", hours, minute, second_hand);
display.setText(time);
try{
Thread.sleep(1000);
}catch (Exception e){
}
}
}
}
以下是LogCat：
02-22 00:03:18.207 13038-13038/? I/art: Late-enabling -Xcheck:jni
02-22 00:03:18.357 13038-13038/com.example.nishant.stopwatch I/InstantRun: Instant Run Runtime started. Android package is com.example.nishant.stopwatch, real application class is null.
02-22 00:03:18.447 13038-13038/com.example.nishant.stopwatch V/Monotype: SetAppTypeFace- try to flip, app = com.example.nishant.stopwatch
02-22 00:03:18.447 13038-13038/com.example.nishant.stopwatch V/Monotype: Typeface getFontPathFlipFont - systemFont = default#default
02-22 00:03:18.457 13038-13038/com.example.nishant.stopwatch V/Monotype: SetAppTypeFace- try to flip, app = com.example.nishant.stopwatch
02-22 00:03:18.457 13038-13038/com.example.nishant.stopwatch V/Monotype: Typeface getFontPathFlipFont - systemFont = default#default
02-22 00:03:18.767 13038-13038/com.example.nishant.stopwatch W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
02-22 00:03:18.817 13038-13038/com.example.nishant.stopwatch V/Monotype: SetAppTypeFace- try to flip, app = com.example.nishant.stopwatch
02-22 00:03:18.817 13038-13038/com.example.nishant.stopwatch V/Monotype: Typeface getFontPathFlipFont - systemFont = default#default
02-22 00:03:19.097 13038-13077/com.example.nishant.stopwatch D/OpenGLRenderer: Render dirty regions requested: true
02-22 00:03:19.107 13038-13038/com.example.nishant.stopwatch D/Atlas: Validating map...
02-22 00:03:19.187 13038-13077/com.example.nishant.stopwatch I/OpenGLRenderer: Initialized EGL, version 1.4
02-22 00:03:19.187 13038-13077/com.example.nishant.stopwatch W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
02-22 00:03:19.187 13038-13077/com.example.nishant.stopwatch D/OpenGLRenderer: Enabling debug mode 0
02-22 00:04:46.007 13038-13047/com.example.nishant.stopwatch I/art: Thread[5,tid=13047,WaitingInMainSignalCatcherLoop,Thread*=0xb7ae7f30,peer=0x12c00080,"Signal Catcher"]: reacting to signal 3
02-22 00:04:46.147 13038-13047/com.example.nishant.stopwatch I/art: Wrote stack traces to '/data/anr/traces.txt'
答案 0 :(得分：2)
尝试以下代码：使用处理程序而不是线程
public class MainActivity extends Activity {
private TextView textTimer;
private Button startButton;
private Button pauseButton;
private long startTime = 0L;
private Handler myHandler = new Handler();
long timeInMillies = 0L;
long timeSwap = 0L;
long finalTime = 0L;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textTimer = (TextView) findViewById(R.id.textView2);
startButton = (Button) findViewById(R.id.start);
startButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
startTime = SystemClock.uptimeMillis();
myHandler.postDelayed(updateTimerMethod, 0);
}
});
pauseButton = (Button) findViewById(R.id.pause);
pauseButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
timeSwap += timeInMillies;
myHandler.removeCallbacks(updateTimerMethod);
}
});
}
private Runnable updateTimerMethod = new Runnable() {
public void run() {
timeInMillies = SystemClock.uptimeMillis() - startTime;
finalTime = timeSwap + timeInMillies;
int seconds = (int) (finalTime / 1000);
int minutes = seconds / 60;
seconds = seconds % 60;
int milliseconds = (int) (finalTime % 1000);
textTimer.setText("" + minutes + ":"
+ String.format("%02d", seconds) + ":"
+ String.format("%03d", milliseconds));
myHandler.postDelayed(this, 0);
}
};
}
答案 1 :(得分：2)
您在主线程中使用无限循环。这使得应用程序无法工作。考虑将手表提取到另一个这样的线程：
public class TimerThread extends Thread {
boolean running;
int second;
int hours;
int minute;
int second_hand;
private Handler h; //Because when updating Views, you must do so from the mainThread
public TimerThread(int seconds) {
second = seconds;
running = true;
h = new Handler();
}
protected void startTimer(){
while (running){
second++;
hours = second/3600;
minute = (second%3600)/60;
second_hand = second%60;
String time = String.format("%02d:%02d;%02d", hours, minute, second_hand);
handler.post(new Runnable() {
run() {
display.setText(time); //You might have to make display final
}
});
try{
Thread.sleep(1000);
}catch (Exception e){
}
}
}
public void stopTimer(){
running = false;
}
public int getSeconds() {
return second;
}
}
在您的活动中：
private TimerThread mTimerThread;
private int seconds;
public void onCreate (...) {
...
start_button.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View v){
if (! running && mTimerThread == null) {
mTimerThread = new TimerThread(seconds);
mTimerThread.start();
}
}
});
pause_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (running && mTimerThread != null){
mTimerThread.stopTimer();
seconds = mTimerThread.getSeconds();
}
}
});
reset_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mTimerThread != null)
mTimerThread.stopTimer();
seconds = 0;
display.setText("");
display.setHint("00:00:00");
}
});