无法解析了空指针异常 [英] Unable to parsing got Null pointer Exception
问题描述
et2.addTextChangedListener(新TextWatcher(){ @覆盖
公共无效onTextChanged(CharSequence中,诠释开始,诠释之前,诠释计数){
// TODO自动生成方法存根
ET2 =(EditText上)findViewById(R.id.editText2);
面积= Math.PI *半径*半径;
字符串名称= Double.toString(区);
et2.setText(名); } @覆盖
公共无效beforeTextChanged(CharSequence中,诠释开始,诠释计数,
INT后){
// TODO自动生成方法存根 } @覆盖
公共无效afterTextChanged(编辑S){
// TODO自动生成方法存根 }
});
19 01-31:05:01.346:D / AndroidRuntime(650):关闭VM
01-31 19:05:01.346:W / dalvikvm(650):主题ID = 1:螺纹未捕获的异常(组= 0x40015560)退出
01-31 19:05:01.366:E / AndroidRuntime(650):致命异常:主要
01-31 19:05:01.366:E / AndroidRuntime(650):了java.lang.RuntimeException:无法启动活动ComponentInfo {com.example.zlistactivity / com.example.zlistactivity.MainActivity}:java.lang.NumberFormatException:
01-31 19:05:01.366:E / AndroidRuntime(650):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
01-31 19:05:01.366:E / AndroidRuntime(650):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
01-31 19:05:01.366:E / AndroidRuntime(650):在android.app.ActivityThread.access $ 1500(ActivityThread.java:117)
01-31 19:05:01.366:E / AndroidRuntime(650):在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:931)
01-31 19:05:01.366:E / AndroidRuntime(650):在android.os.Handler.dispatchMessage(Handler.java:99)
01-31 19:05:01.366:E / AndroidRuntime(650):在android.os.Looper.loop(Looper.java:123)
01-31 19:05:01.366:E / AndroidRuntime(650):在android.app.ActivityThread.main(ActivityThread.java:3683)
01-31 19:05:01.366:E / AndroidRuntime(650):在java.lang.reflect.Method.invokeNative(本机方法)
01-31 19:05:01.366:E / AndroidRuntime(650):在java.lang.reflect.Method.invoke(Method.java:507)
01-31 19:05:01.366:E / AndroidRuntime(650):在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:839)
01-31 19:05:01.366:E / AndroidRuntime(650):在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
01-31 19:05:01.366:E / AndroidRuntime(650):在dalvik.system.NativeStart.main(本机方法)
01-31 19:05:01.366:E / AndroidRuntime(650):java.lang.NumberFormatException:产生的原因:
01-31 19:05:01.366:E / AndroidRuntime(650):在org.apache.harmony.luni.util.FloatingPointParser.parseDouble(FloatingPointParser.java:267)
01-31 19:05:01.366:E / AndroidRuntime(650):在java.lang.Double.parseDouble(Double.java:318)
01-31 19:05:01.366:E / AndroidRuntime(650):在java.lang.Double.valueOf(Double.java:356)
01-31 19:05:01.366:E / AndroidRuntime(650):在com.example.zlistactivity.MainActivity.onCreate(MainActivity.java:22)
01-31 19:05:01.366:E / AndroidRuntime(650):在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
01-31 19:05:01.366:E / AndroidRuntime(650):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
01-31 19:05:01.366:E / AndroidRuntime(650):11 ...更多
01-31 19:05:05.156:I /流程(650):发送信号。 PID:650 SIG:9
声明你的EditText的Textchange听众面前:
ET2 =(EditText上)findViewById(R.id.editText2);
et2.addTextChangedListener(新TextWatcher(){
@覆盖
公共无效onTextChanged(CharSequence中,诠释开始,诠释之前,诠释计数){
// TODO自动生成方法存根
面积= Math.PI *半径*半径;
字符串名称= Double.toString(区);
et2.setText(名);
}
块引用>et2.addTextChangedListener(new TextWatcher() { @Override public void onTextChanged(CharSequence s, int start, int before, int count) { // TODO Auto-generated method stub et2 = (EditText) findViewById(R.id.editText2); area = Math.PI * radius * radius; String name = Double.toString(area); et2.setText(name); } @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) { // TODO Auto-generated method stub } @Override public void afterTextChanged(Editable s) { // TODO Auto-generated method stub } });
01-31 19:05:01.346: D/AndroidRuntime(650): Shutting down VM 01-31 19:05:01.346: W/dalvikvm(650): threadid=1: thread exiting with uncaught exception (group=0x40015560) 01-31 19:05:01.366: E/AndroidRuntime(650): FATAL EXCEPTION: main 01-31 19:05:01.366: E/AndroidRuntime(650): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.zlistactivity/com.example.zlistactivity.MainActivity}: java.lang.NumberFormatException: 01-31 19:05:01.366: E/AndroidRuntime(650): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 01-31 19:05:01.366: E/AndroidRuntime(650): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 01-31 19:05:01.366: E/AndroidRuntime(650): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 01-31 19:05:01.366: E/AndroidRuntime(650): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 01-31 19:05:01.366: E/AndroidRuntime(650): at android.os.Handler.dispatchMessage(Handler.java:99) 01-31 19:05:01.366: E/AndroidRuntime(650): at android.os.Looper.loop(Looper.java:123) 01-31 19:05:01.366: E/AndroidRuntime(650): at android.app.ActivityThread.main(ActivityThread.java:3683) 01-31 19:05:01.366: E/AndroidRuntime(650): at java.lang.reflect.Method.invokeNative(Native Method) 01-31 19:05:01.366: E/AndroidRuntime(650): at java.lang.reflect.Method.invoke(Method.java:507) 01-31 19:05:01.366: E/AndroidRuntime(650): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 01-31 19:05:01.366: E/AndroidRuntime(650): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 01-31 19:05:01.366: E/AndroidRuntime(650): at dalvik.system.NativeStart.main(Native Method) 01-31 19:05:01.366: E/AndroidRuntime(650): Caused by: java.lang.NumberFormatException: 01-31 19:05:01.366: E/AndroidRuntime(650): at org.apache.harmony.luni.util.FloatingPointParser.parseDouble(FloatingPointParser.java:267) 01-31 19:05:01.366: E/AndroidRuntime(650): at java.lang.Double.parseDouble(Double.java:318) 01-31 19:05:01.366: E/AndroidRuntime(650): at java.lang.Double.valueOf(Double.java:356) 01-31 19:05:01.366: E/AndroidRuntime(650): at com.example.zlistactivity.MainActivity.onCreate(MainActivity.java:22) 01-31 19:05:01.366: E/AndroidRuntime(650): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 01-31 19:05:01.366: E/AndroidRuntime(650): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 01-31 19:05:01.366: E/AndroidRuntime(650): ... 11 more 01-31 19:05:05.156: I/Process(650): Sending signal. PID: 650 SIG: 9
解决方案Declare your edittext before the Textchange listener :
et2 = (EditText) findViewById(R.id.editText2); et2.addTextChangedListener(new TextWatcher() { @Override public void onTextChanged(CharSequence s, int start, int before, int count){ // TODO Auto-generated method stub area = Math.PI * radius * radius; String name = Double.toString(area); et2.setText(name); }
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