我希望用户在编辑文本框中输入分钟，然后在单击提交按钮时，计数器将启动。但这里的错误是什么？它表明，不幸的是应用程序已停止。请帮忙。
package com.example.asifsabir.counterapps;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.util.concurrent.TimeUnit;
public class MainActivity extends AppCompatActivity {
TextView tv1;
EditText et1;
Button bt1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv1 = (TextView) findViewById(R.id.textView1);
et1 =(EditText) findViewById(R.id.et1);
bt1= (Button) findViewById(R.id.bt1);
bt1.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
int min =Integer.parseInt(et1.getText().toString());
if (!et1.getText().toString().isEmpty()){
final int sec = min*60;
new CountDownTimer(sec, 1000) {
public void onTick(long millisUntilFinished) {
tv1.setText("" + String.format("%02d:%02d",
TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished) - TimeUnit.HOURS.toMinutes(
TimeUnit.MILLISECONDS.toHours(millisUntilFinished)),
TimeUnit.MILLISECONDS.toSeconds(millisUntilFinished) - TimeUnit.MINUTES.toSeconds(
TimeUnit.MILLISECONDS.toMinutes(millisUntilFinished))));
}
public void onFinish() {
tv1.setText("done!");
}
}.start();
}
}
}
);
}
}
，xml代码为：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/et1"
android:paddingLeft="50dp"
android:paddingRight="50dp"
android:inputType="number"
android:hint="enter sec"
android:textAlignment="center"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/bt1"
android:layout_gravity="center"
android:text="submit"/>
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="count"
android:layout_marginTop="100dp"
android:layout_gravity="center"
android:textColor="#3559da"
android:textSize="80sp" />
</LinearLayout>
错误日志：
339-25339/? I/art: Late-enabling -Xcheck:jni
03-24 05:25:44.927 25339-25339/? I/art: VMHOOK: rlim_cur : 0 pid:25339
03-24 05:25:44.957 25339-25353/? I/art: Debugger is no longer active
03-24 05:25:45.127 25339-25339/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.asifsabir.counterapps, PID: 25339
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.asifsabir.counterapps/com.example.asifsabir.counterapps.MainActivity}: java.lang.NumberFormatException: Invalid int: ""
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2411)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2474)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1359)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:155)
at android.app.ActivityThread.main(ActivityThread.java:5702)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1029)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:824)
Caused by: java.lang.NumberFormatException: Invalid int: ""
at java.lang.Integer.invalidInt(Integer.java:138)
at java.lang.Integer.parseInt(Integer.java:358)
at java.lang.Integer.parseInt(Integer.java:334)
at com.example.asifsabir.counterapps.MainActivity.onCreate(MainActivity.java:29)
at android.app.Activity.performCreate(Activity.java:5958)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1129)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2364)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2474)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1359)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:155)
at android.app.ActivityThread.main(ActivityThread.java:5702)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1029)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:824)
03-24 05:28:37.087 25339-25339/com.example.asifsabir.counterapps D/Process: killProcess, pid=25339
03-24 05:28:37.087 25339-25339/com.example.asifsabir.counterapps D/Process: com.android.internal.os.RuntimeInit$UncaughtHandler.uncaughtException:138 java.lang.ThreadGroup.uncaughtException:693 java.lang.ThreadGroup.uncaughtException:690
答案 0 :(得分：0)
当点击事件发生时你应该得到Integer.parseInt，你的输入必须是毫秒：
bt1.setOnClickListener(
new View.OnClickListener() {
@Override
public void onClick(View v) {
int min = Integer.parseInt(et1.getText().toString());
int sec = min*60;
int millis = sec*1000;
new CountDownTimer(millis, 1000) {
//(...)
如果EditText不为空，你还应该验证，以避免像你得到的NumberFormat异常。
if (et1.getText().toString().isEmpty())
//notice user to input some number
return;
答案 1 :(得分：0)
您正尝试将EditText值转换为onCreate() -
int min =Integer.parseInt(et1.getText().toString());
现在在onCreate()，那时你的
EditText将为空
et1.getText().toString()将为""
因此
Integer.parseInt("")显然会抛出NumberFormatException
要避免这种情况，您需要做两件最重要的事情 -
首先检查空字符串
if (!et1.getText().toString().isEmpty()){
//convert here
}
同时让xml中的EditText仅接受数字，以便将来不再发送NumberFormatException。