[英]Android Studio error: Unfortunately My Own App has stopped
希望您能帮我这个小代码。 我收到以下错误:
--------- beginning of crash
05-06 23:00:26.734 1904-1904/com.example.alexismoralesgamboa.myownapp E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.alexismoralesgamboa.myownapp, PID: 1904
java.lang.IllegalStateException: Could not execute method of the activity
at android.view.View$1.onClick(View.java:4007)
at android.view.View.performClick(View.java:4756)
at android.view.View$PerformClick.run(View.java:19749)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
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:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at android.view.View$1.onClick(View.java:4002)
at android.view.View.performClick(View.java:4756)
at android.view.View$PerformClick.run(View.java:19749)
at android.os.Handler.handleCallback(Handler.java:739
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at com.example.alexismoralesgamboa.myownapp.MainActivity.onButtonClick(MainActivity.j ava:47)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at android.view.View$1.onClick(View.java:4002)
at android.view.View.performClick(View.java:4756)
at android.view.View$PerformClick.run(View.java:19749)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
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:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
这是我的主要活动java文件:
package com.example.alexismoralesgamboa.myownapp;
import android.preference.CheckBoxPreference;
import android.support.v7.app.ActionBarActivity;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.CheckBox;
import android.widget.TextView;
public class MainActivity extends ActionBarActivity {
TextView textView;
CheckBox pepBox, cheeseBox;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
pepBox = (CheckBox) findViewById(R.id.checkBox);
cheeseBox = (CheckBox) findViewById(R.id.checkBox2);
textView = (TextView) findViewById(R.id.textView);
}
public void onButtonClick(final View view){
StringBuilder str = new StringBuilder("");
if(pepBox.isChecked()) {
str.append("Pepperoni" + " ");
}
if(cheeseBox.isChecked()) {
str.append("Extra Cheese");
}
if(str.length() == 0) {
str.append("Plain");
}
textView.setText(str);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
强文本
我的清单:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.alexismoralesgamboa.myownapp" >
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
</activity>
</application>
这是我的活动主要xml:
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Pepperoni"
android:id="@+id/checkBox"
android:layout_centerHorizontal="true"
android:layout_marginTop="60dp"
android:checked="false" />
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Extra Cheese"
android:id="@+id/checkBox2"
android:layout_below="@+id/checkBox"
android:layout_centerHorizontal="true"
android:checked="false" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Show"
android:id="@+id/button"
android:layout_below="@+id/checkBox2"
android:layout_alignRight="@+id/checkBox2"
android:layout_alignEnd="@+id/checkBox2"
android:onClick="onButtonClick" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Plain"
android:id="@+id/TextView"
android:layout_below="@+id/button"
android:layout_centerHorizontal="true" />
当我单击应用程序上的按钮时,就会发生问题。
希望你能帮我! 谢谢!
您正在扩展ActionBarActivity。如果您不需要任何具有相同功能的功能,也可以将其更改为Activity
也可以更改导入部分。通常是因为这个原因。
问题是您的TextView
命名不匹配,因此在调用setText()
时textView
为null。
在您的代码中:
textView = (TextView) findViewById(R.id.textView);
在您的xml中:
android:id="@+id/TextView"
要解决此问题,只需将xml更改为:
android:id="@+id/textView"
首先,将意图过滤器添加到清单中,否则您的应用甚至不会显示在设备中,请将以下代码行添加到清单中
<activity
android:name=".MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
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