我正在尝试通过从edittext获取值并将其转换为整数来更新intdelay，如下所示，我正在使用toast来检查intdelay的更新值。
public static int intdelay=1000;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
delayedttxt=(EditText)findViewById(R.id.delayedttxt);
String delay=delayedttxt.getText().toString(); //this will get a string
try{
int intdelay = Integer.parseInt(delay);
}catch(NumberFormatException ex){ // handle your exception
}
Button btn=(Button)findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
flashLight.switchFlash();
Toast.makeText(MainActivity.this,"your integer is " + intdelay , Toast.LENGTH_LONG).show();
}
});
但intdelay值未更新。
我怎么解决这个问题？
注意：我必须使用try-catch结构，否则应用程序会崩溃。
当我删除try-catch时 代码如下：
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
delayedttxt=(EditText)findViewById(R.id.delayedttxt);
String delay=delayedttxt.getText().toString();
final int intdelay = Integer.parseInt(delay);
Button btn=(Button)findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
flashLight.switchFlash();
Toast.makeText(MainActivity.this,"your integer is " + intdelay ,Toast.LENGTH_LONG).show();
}
});
崩溃后的logcat如下：
08-22 16:13:05.866 17636-17636/de.nocnoc.clean.cleanlight I/RequestQueue: Repeating capture request set.
08-22 16:13:05.876 17636-17790/de.nocnoc.clean.cleanlight W/LegacyRequestMapper: convertRequestMetadata - control.awbRegions setting is not supported, ignoring value
08-22 16:13:05.876 17636-17790/de.nocnoc.clean.cleanlight W/LegacyRequestMapper: Only received metering rectangles with weight 0.
08-22 16:13:06.866 17636-17636/de.nocnoc.clean.cleanlight I/RequestQueue: Repeating capture request cancelled.
08-22 16:13:06.866 17636-17636/de.nocnoc.clean.cleanlight I/RequestQueue: Repeating capture request set.
08-22 16:13:06.894 17636-17790/de.nocnoc.clean.cleanlight W/LegacyRequestMapper: convertRequestMetadata - control.awbRegions setting is not supported, ignoring value
08-22 16:13:06.894 17636-17790/de.nocnoc.clean.cleanlight W/LegacyRequestMapper: Only received metering rectangles with weight 0.
08-22 16:19:51.367 19348-19348/de.nocnoc.clean.cleanlight W/System: ClassLoader referenced unknown path: /data/app/de.nocnoc.clean.cleanlight-2/lib/arm
08-22 16:19:51.404 19348-19348/de.nocnoc.clean.cleanlight D/AndroidRuntime: Shutting down VM
08-22 16:19:51.414 19348-19348/de.nocnoc.clean.cleanlight E/AndroidRuntime: FATAL EXCEPTION: main
Process: de.nocnoc.clean.cleanlight, PID: 19348
java.lang.RuntimeException: Unable to start activity ComponentInfo{de.nocnoc.clean.cleanlight/de.nocnoc.clean.flashlight.MainActivity}: java.lang.NumberFormatException: Invalid int: ""
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2464)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2524)
at android.app.ActivityThread.access$900(ActivityThread.java:154)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1391)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:234)
at android.app.ActivityThread.main(ActivityThread.java:5526)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
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 de.nocnoc.clean.flashlight.MainActivity.onCreate(MainActivity.java:32)
at android.app.Activity.performCreate(Activity.java:6285)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1108)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2417)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2524)
at android.app.ActivityThread.access$900(ActivityThread.java:154)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1391)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:234)
at android.app.ActivityThread.main(ActivityThread.java:5526)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
08-22 16:19:53.050 19348-19348/de.nocnoc.clean.cleanlight I/Process: Sending signal. PID: 19348 SIG: 9
答案 0 :(得分：1)
您只在intdelay获得onCreate，您应该在每次显示吐司之前阅读编辑文本的值。换句话说，在onClickListener内。最初编辑文本中没有任何值，因此Integer.parseInt调用将throw NumberFormatException。
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String delay = delayedttxt.getText().toString();
int intdelay = 0;
try{
intdelay = Integer.parseInt(delay);
} catch(NumberFormatException ex){
e.printStackTrace();// Never swallow exception
}
flashLight.switchFlash();
Toast.makeText("Initial Delay : " + intdelay , Toast.LENGTH_LONG).show();
}
});
答案 1 :(得分：0)
这种情况正在发生，因为在edittext中设置任何值之前，延迟会被初始化。移动这一行
String delay=delayedttxt.getText().toString();
在onclick方法中，像这样 -
Button btn=(Button)findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String delay=delayedttxt.getText().toString();
flashLight.switchFlash();
Toast.makeText(MainActivity.this,"your integer is " + intdelay , Toast.LENGTH_LONG).show();
}
});
然后再试一次
答案 2 :(得分：0)
你应该把
String delay=delayedttxt.getText().toString(); //this will get a string
try{
int intdelay = Integer.parseInt(delay);
}catch(NumberFormatException ex){ // handle your exception
}
在onclicklistener中 它正在抛出NumberFormatException，因为你正在解析getText方法返回的空字符串 这样做之后不需要尝试捕获