我尽我所能来解决这个问题，但从未成功过，我也环顾网络，但没找到我想要的东西。
因此。我正在研究秒表应用程序，我希望它显示毫秒，但我无法显示正确的摘要，因为我只希望它显示厘秒，我的意思是两位数，从00到99然后1秒过去了。
当我使用下面的代码运行应用程序时，它看起来像在模拟器中，我工作，（不能说，因为模拟器是缓慢和滞后的），但当我在我的galaxy nexus 4.1上运行它。 1我强行关闭。
非常感谢任何帮助
以下是毫秒字符串的代码：
milliseconds = String.valueOf((long)time);
if(milliseconds.length()==3){
milliseconds = "0"+milliseconds;
}
if(milliseconds.length()<=1){
milliseconds = "00";
}
milliseconds = milliseconds.substring(milliseconds.length()-3, milliseconds.length()-1);
完整的java：
package com.tutorial.stopwatch;
import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.view.Menu;
import android.app.Activity;
import android.content.res.Configuration;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.graphics.Typeface;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.view.View;
import android.widget.Button;
public class MainActivity extends Activity {
private TextView tempTextView; //Temporary TextView
private Button tempBtn; //Temporary Button
private Handler mHandler = new Handler();
private long startTime;
private long elapsedTime;
private final int REFRESH_RATE = 100;
private String hours,minutes,seconds,milliseconds;
private long secs,mins,hrs,msecs;
private boolean stopped = false;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
checkScreenDensity();
/*-------Setting the TextView Fonts-----------*/
Typeface fonttimer = Typeface.createFromAsset(getAssets(), "roboto.ttf");
tempTextView = (TextView) findViewById(R.id.timer);
tempTextView.setTypeface(fonttimer);
tempTextView = (TextView) findViewById(R.id.timerMs);
tempTextView.setTypeface(fonttimer);
tempTextView = (TextView) findViewById(R.id.timerHs);
tempTextView.setTypeface(fonttimer);
Typeface font = Typeface.createFromAsset(getAssets(), "roboto.ttf");
tempTextView = (TextView) findViewById(R.id.backgroundText);
tempTextView.setTypeface(font);
Button tempBtn = (Button)findViewById(R.id.startButton);
tempBtn.setTypeface(font);
tempBtn = (Button)findViewById(R.id.resetButton);
tempBtn.setTypeface(font);
tempBtn = (Button)findViewById(R.id.stopButton);
tempBtn.setTypeface(font);
}
private void checkScreenDensity(){
tempTextView = (TextView)findViewById(R.id.backgroundText);
switch (getResources().getDisplayMetrics().densityDpi) {
case DisplayMetrics.DENSITY_LOW:
tempTextView.setVisibility(View.GONE);
break;
case DisplayMetrics.DENSITY_MEDIUM:
tempTextView.setVisibility(View.GONE);
break;
case DisplayMetrics.DENSITY_HIGH:
tempTextView.setVisibility(View.VISIBLE);
break;
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
//---------- on click procedures - id from layout.xml -----------
public void startClick (View view){
showStopButton();
if(stopped){
startTime = System.currentTimeMillis() - elapsedTime;
}
else{
startTime = System.currentTimeMillis();
}
mHandler.removeCallbacks(startTimer);
mHandler.postDelayed(startTimer, 0);
}
public void stopClick (View view){
hideStopButton();
mHandler.removeCallbacks(startTimer);
stopped = true;
}
public void resetClick (View view){
hideStopButton();
mHandler.removeCallbacks(startTimer);
stopped = false;
((TextView)findViewById(R.id.timer)).setText("00:00");
((TextView)findViewById(R.id.timerMs)).setText(":00");
((TextView)findViewById(R.id.timerHs)).setText("00:");
}
//---------- Button change (start/reset to stop button)
private void showStopButton(){
((Button)findViewById(R.id.startButton)).setVisibility(View.GONE);
((Button)findViewById(R.id.resetButton)).setVisibility(View.VISIBLE);
((Button)findViewById(R.id.stopButton)).setVisibility(View.VISIBLE);
}
private void hideStopButton(){
((Button)findViewById(R.id.startButton)).setVisibility(View.VISIBLE);
((Button)findViewById(R.id.resetButton)).setVisibility(View.VISIBLE);
((Button)findViewById(R.id.stopButton)).setVisibility(View.GONE);
}
//-------- time from MiliSeconds to regular time ---------------------------------
private void updateTimer (float time){
secs = (long)(time/1000);
mins = (long)((time/1000)/60);
hrs = (long)(((time/1000)/60)/60);
/* Setting the timer text to the elapsed time */
((TextView)findViewById(R.id.timerHs)).setText(hours + ":");
((TextView)findViewById(R.id.timer)).setText(minutes + ":" + seconds);
((TextView)findViewById(R.id.timerMs)).setText(":" + milliseconds);
/* Convert the seconds to String
* and format to ensure it has
* a leading zero when required
*/
secs = secs % 60;
seconds=String.valueOf(secs);
if(secs == 0){
seconds = "00";
}
if(secs <10 && secs > 0){
seconds = "0"+seconds;
}
/* Convert the minutes to String and format the String */
mins = mins % 60;
minutes=String.valueOf(mins);
if(mins == 0){
minutes = "00";
}
if(mins <10 && mins > 0){
minutes = "0"+minutes;
}
/* Convert the hours to String and format the String */
hours=String.valueOf(hrs);
if(hrs == 0){
hours = "00";
}
if(hrs <10 && hrs > 0){
hours = "0"+hours;
}
/* milliseconds */
milliseconds = String.valueOf((long)time);
if(milliseconds.length()==3){
milliseconds = "0"+milliseconds;
}
if(milliseconds.length()<=1){
milliseconds = "00";
}
milliseconds = milliseconds.substring(milliseconds.length()-3, milliseconds.length()-1);
}
//------------- Timer Runnnable -----------------------------------------------------------
private Runnable startTimer = new Runnable() {
public void run() {
elapsedTime = System.currentTimeMillis() - startTime;
updateTimer(elapsedTime);
mHandler.postDelayed(this,REFRESH_RATE);
}
};
//------------------ screen orientation fix -----------------------------------------------------------
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {
TextView timer = (TextView) findViewById(R.id.timer);
timer.setTextSize(TypedValue.COMPLEX_UNIT_SP, 90);
TextView timerMs = (TextView) findViewById(R.id.timerMs);
timerMs.setTextSize(TypedValue.COMPLEX_UNIT_SP, 40);
}
else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT) {
TextView timer = (TextView) findViewById(R.id.timer);
timer.setTextSize(TypedValue.COMPLEX_UNIT_SP, 70);
TextView timerMs = (TextView) findViewById(R.id.timerMs);
timerMs.setTextSize(TypedValue.COMPLEX_UNIT_SP, 30);
}
}
}
更新：
我编辑了代码以适应我的布局，但我崩溃了：
private void updateTimer (long time) {
Calendar c = Calendar.getInstance();
c.setTimeInMillis(time);
// This will output one string in Hour:Minute:Seconds: with zeroes added
String h = String.format("%1$tH", c);
String ms = String.format("%1$tM:%1$tS", c);
// Unfortunately, theres no format specifier for centiseconds, so we'll have
// to make do with the substring of ms
String cs = String.format("%1$L").substring(0,2);
String printMe = h + ms + cs;
/* Setting the timer text to the elapsed time */
((TextView)findViewById(R.id.timerHs)).setText(h);
((TextView)findViewById(R.id.timer)).setText(ms);
((TextView)findViewById(R.id.timerMs)).setText(cs);
}
记录：
09-28 19:32:29.986: D/dalvikvm(1832): GC_FOR_ALLOC freed 42K, 4% free 8005K/8259K, paused 112ms, total 118ms
09-28 19:32:30.008: I/dalvikvm-heap(1832): Grow heap (frag case) to 9.331MB for 1536016-byte allocation
09-28 19:32:30.116: D/dalvikvm(1832): GC_CONCURRENT freed <1K, 4% free 9504K/9799K, paused 33ms+17ms, total 109ms
09-28 19:32:30.426: D/dalvikvm(1832): GC_FOR_ALLOC freed 3K, 2% free 9864K/10055K, paused 40ms, total 41ms
09-28 19:32:30.756: D/gralloc_goldfish(1832): Emulator without GPU emulation detected.
09-28 19:32:41.536: D/AndroidRuntime(1832): Shutting down VM
09-28 19:32:41.588: W/dalvikvm(1832): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
09-28 19:32:41.646: E/AndroidRuntime(1832): FATAL EXCEPTION: main
09-28 19:32:41.646: E/AndroidRuntime(1832): java.util.MissingFormatArgumentException: Format specifier: 1$L
09-28 19:32:41.646: E/AndroidRuntime(1832): at java.util.Formatter.getArgument(Formatter.java:1109)
09-28 19:32:41.646: E/AndroidRuntime(1832): at java.util.Formatter.doFormat(Formatter.java:1074)
09-28 19:32:41.646: E/AndroidRuntime(1832): at java.util.Formatter.format(Formatter.java:1040)
09-28 19:32:41.646: E/AndroidRuntime(1832): at java.util.Formatter.format(Formatter.java:1009)
09-28 19:32:41.646: E/AndroidRuntime(1832): at java.lang.String.format(String.java:1998)
09-28 19:32:41.646: E/AndroidRuntime(1832): at java.lang.String.format(String.java:1972)
09-28 19:32:41.646: E/AndroidRuntime(1832): at com.tutorial.stopwatch.MainActivity.updateTimer(MainActivity.java:138)
09-28 19:32:41.646: E/AndroidRuntime(1832): at com.tutorial.stopwatch.MainActivity.access$3(MainActivity.java:129)
09-28 19:32:41.646: E/AndroidRuntime(1832): at com.tutorial.stopwatch.MainActivity$1.run(MainActivity.java:155)
09-28 19:32:41.646: E/AndroidRuntime(1832): at android.os.Handler.handleCallback(Handler.java:615)
09-28 19:32:41.646: E/AndroidRuntime(1832): at android.os.Handler.dispatchMessage(Handler.java:92)
09-28 19:32:41.646: E/AndroidRuntime(1832): at android.os.Looper.loop(Looper.java:137)
09-28 19:32:41.646: E/AndroidRuntime(1832): at android.app.ActivityThread.main(ActivityThread.java:4745)
09-28 19:32:41.646: E/AndroidRuntime(1832): at java.lang.reflect.Method.invokeNative(Native Method)
09-28 19:32:41.646: E/AndroidRuntime(1832): at java.lang.reflect.Method.invoke(Method.java:511)
09-28 19:32:41.646: E/AndroidRuntime(1832): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
09-28 19:32:41.646: E/AndroidRuntime(1832): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
09-28 19:32:41.646: E/AndroidRuntime(1832): at dalvik.system.NativeStart.main(Native Method)
谢谢！
答案 0 :(得分：0)
来自：http://www.java2s.com/Code/Java/Language-Basics/JavaformattedIOtheprecisionmodifier.htm
import java.util.Formatter;
公共类MainClass { public static void main（String args []）{ Formatter fmt = new Formatter（）;
// Format 4 decimal places.
fmt.format("%.4f", 123.1234567);
System.out.println(fmt);
// Format to 2 decimal places in a 16 character field.
fmt = new Formatter();
fmt.format("%16.2e", 123.1234567);
System.out.println(fmt);
// Display at most 15 characters in a string.
fmt = new Formatter();
fmt.format("%.15s", "Formatting with Java is now easy.");
System.out.println(fmt);
} }
基本上你想要类似fmt.format（“％。2d”，decimalNumberValue）;
当然，您可以使用数字操作构建自己的数字，但这已内置到库中。
答案 1 :(得分：0)
你为什么用字符串来处理你的时代？这只会让你感到痛苦和痛苦:) Java格式化程序有更好的方法来处理时间：
// Note the long type here - that's what you're passing in anyway, best make it
// official
private void updateTimer (long time) {
Calendar c = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
c.setTimeMillis(time);
// This will output one string in Hour:Minute:Seconds: with zeroes added
String hms = String.format("%1$tH:%1$tM:%1$tS:", c);
// Unfortunately, theres no format specifier for centiseconds, so we'll have
// to make do with the substring of ms
String cs = String.format("%1$tL", c).substring(0,2);
String printMe = hms + cs
}
请参阅formatter了解更多