我打开Android应用程序时一直出错
应用程序app_name（进程com.random.stuff）意外停止。 请再试一次
logcat的
04-04 05:51:39.975: D/AndroidRuntime(480): Shutting down VM
04-04 05:51:39.975: W/dalvikvm(480): threadid=1: thread exiting with uncaught exception (group=0x40015560)
04-04 05:51:40.076: E/AndroidRuntime(480): FATAL EXCEPTION: main
04-04 05:51:40.076: E/AndroidRuntime(480): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.thenewboston.joseph/com.random.stuff.StartingPoint}: java.lang.NullPointerException
04-04 05:51:40.076: E/AndroidRuntime(480): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1569)
04-04 05:51:40.076: E/AndroidRuntime(480): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
04-04 05:51:40.076: E/AndroidRuntime(480): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
04-04 05:51:40.076: E/AndroidRuntime(480): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
04-04 05:51:40.076: E/AndroidRuntime(480): at android.os.Handler.dispatchMessage(Handler.java:99)
04-04 05:51:40.076: E/AndroidRuntime(480): at android.os.Looper.loop(Looper.java:123)
04-04 05:51:40.076: E/AndroidRuntime(480): at android.app.ActivityThread.main(ActivityThread.java:3683)
04-04 05:51:40.076: E/AndroidRuntime(480): at java.lang.reflect.Method.invokeNative(Native Method)
04-04 05:51:40.076: E/AndroidRuntime(480): at java.lang.reflect.Method.invoke(Method.java:507)
04-04 05:51:40.076: E/AndroidRuntime(480): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
04-04 05:51:40.076: E/AndroidRuntime(480): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
04-04 05:51:40.076: E/AndroidRuntime(480): at dalvik.system.NativeStart.main(Native Method)
04-04 05:51:40.076: E/AndroidRuntime(480): Caused by: java.lang.NullPointerException
04-04 05:51:40.076: E/AndroidRuntime(480): at com.random.stuff.StartingPoint.(StartingPoint.java:17)
04-04 05:51:40.076: E/AndroidRuntime(480): at java.lang.Class.newInstanceImpl(Native Method)
04-04 05:51:40.076: E/AndroidRuntime(480): at java.lang.Class.newInstance(Class.java:1409)
04-04 05:51:40.076: E/AndroidRuntime(480): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
04-04 05:51:40.076: E/AndroidRuntime(480): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1561)
04-04 05:51:40.076: E/AndroidRuntime(480): ... 11 more
起点：
package com.thenewboston.joseph;
import android.os.Bundle;
import android.app.Activity;
import android.text.Editable;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
@SuppressWarnings("unused")
public class StartingPoint extends Activity {
Button bGuess;
TextView points, hint, result;
EditText guess;
String dog = "Dog";
String guessDog = guess.toString();
int point = 0;
boolean isDog = ((String) hintp).contains("Has four legs and fur");
boolean isFrog = ((String) hintp).contains("Has four legs and is slimy");
boolean wrong;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_starting_point);
bGuess = (Button) findViewById(R.id.bGuess);
points = (TextView) findViewById(R.id.tPoints);
hint = (TextView) findViewById(R.id.tHint);
result = (TextView) findViewById(R.id.tResult);
guess = (EditText) findViewById(R.id.eGuess);
bGuess.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
hint.setText("Has four legs and fur");
if (isDog) {
if ("dog".equals(guess.getText().toString())) {
wrong = false;
hint.setText("Has four legs and is slimy");
}
} else {
wrong = true;
}
if (isFrog) {
if ("frog".equals(guess.getText().toString())) {
wrong = false;
}
} else {
wrong = true;
}
if (wrong) {
point--;
result.setText("False try again");
points.setText("Points: " + point);
}else{
point++;
result.setText("Correct");
points.setText("Points: " + point);
}
}
});
}
}
DDMS专线：
04-04 08:30:28.194: I/DEBUG(31): debuggerd: Feb 3 2011 14:45:34
04-04 08:30:28.225: D/qemud(38): entering main loop
04-04 08:30:28.244: I/Vold(29): Vold 2.1 (the revenge) firing up
04-04 08:30:28.264: I/Netd(30): Netd 1.0 starting
04-04 08:30:28.274: D/Vold(29): USB mass storage support is not enabled in the kernel
04-04 08:30:28.274: D/Vold(29): usb_configuration switch is not enabled in the kernel
04-04 08:30:28.274: D/Vold(29): Volume sdcard state changing -1 (Initializing) -> 0 (No-Media)
04-04 08:30:28.504: D/Vold(29): Volume sdcard state changing 0 (No-Media) -> 1 (Idle-Unmounted)
04-04 08:30:28.565: D/qemud(38): fdhandler_accept_event: accepting on fd 9
04-04 08:30:28.565: D/qemud(38): created client 0xe078 listening on fd 10
04-04 08:30:28.565: D/qemud(38): client_fd_receive: attempting registration for service 'boot-properties'
04-04 08:30:28.565: D/qemud(38): client_fd_receive: -> received channel id 1
04-04 08:30:28.574: D/qemud(38): client_registration: registration succeeded for client 1
04-04 08:30:28.574: I/qemu-props(52): connected to 'boot-properties' qemud service.
04-04 08:30:28.574: I/qemu-props(52): receiving..
04-04 08:30:28.584: I/qemu-props(52): received: dalvik.vm.heapsize=32m
04-04 08:30:28.584: I/qemu-props(52): receiving..
04-04 08:30:28.584: I/qemu-props(52): received: qemu.sf.lcd_density=240
04-04 08:30:28.584: I/qemu-props(52): receiving..
04-04 08:30:28.584: I/qemu-props(52): received: qemu.hw.mainkeys=1
04-04 08:30:28.584: I/qemu-props(52): receiving..
04-04 08:30:28.584: I/qemu-props(52): received: qemu.sf.fake_camera=none
04-04 08:30:28.584: I/qemu-props(52): receiving..
04-04 08:30:28.584: I/qemu-props(52): exiting (4 properties set).
04-04 08:30:28.584: D/qemud(38): fdhandler_event: disconnect on fd 10
04-04 08:30:29.084: D/AndroidRuntime(33): >>>>>> AndroidRuntime START com.android.internal.os.ZygoteInit <<<<<<
04-04 08:30:29.084: D/AndroidRuntime(33): CheckJNI is ON
04-04 08:30:29.314: I/(34): ServiceManager: 0xad50
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".StartingPoint" >
<Button
android:id="@+id/bGuess"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:text="Guess" />
<TextView
android:id="@+id/tPoints"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignRight="@+id/bGuess"
android:text="Points: " />
<TextView
android:id="@+id/tResult"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/tHint"
android:layout_centerHorizontal="true"
android:layout_marginBottom="74dp"
android:text="Result: "
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="@+id/tHint"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:text="Hint: \n"
android:textAppearance="?android:attr/textAppearanceLarge" />
<EditText
android:id="@+id/eGuess"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/bGuess"
android:layout_alignLeft="@+id/bGuess"
android:layout_alignRight="@+id/bGuess"
android:ems="10" />
</RelativeLayout>
答案 0 :(得分：1)
由于此行NullPointerExcetion
String guessDog = guess.toString();
只需将其替换为String guessDog;
现在获取onClick（）方法的文本，如下所示，
public void onClick(View v) {
guessDog = guess.getText().toString(); // Add this line
.
.
以下是我方的更新代码，我做了一些初步修改
true 这是我的代码，
@SuppressWarnings("unused")
public class StartingPoint extends Activity
{
Button bGuess;
TextView points, hint, result;
EditText guess;
String dog = "Dog";
String guessDog;
int point = 0;
boolean isDog = true;
boolean isFrog = true;
boolean wrong;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_starting_point);
bGuess = (Button) findViewById(R.id.bGuess);
points = (TextView) findViewById(R.id.tPoints);
hint = (TextView) findViewById(R.id.tHint);
result = (TextView) findViewById(R.id.tResult);
guess = (EditText) findViewById(R.id.eGuess);
bGuess.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v)
{
guessDog = guess.toString();
// TODO Auto-generated method stub
hint.setText("Has four legs and fur");
if (isDog) {
if ("dog".equals(guess.getText().toString())) {
wrong = false;
hint.setText("Has four legs and is slimy");
}
} else {
wrong = true;
}
if (isFrog) {
if ("frog".equals(guess.getText().toString())) {
wrong = false;
}
} else {
wrong = true;
}
if (wrong) {
point--;
result.setText("False try again");
points.setText("Points: " + point);
}else{
point++;
result.setText("Correct");
points.setText("Points: " + point);
}
}
});
}
}