我的应用程序构建并显示成功,但是当我在手机上打开它时退出而没有启动。我的清单文件有问题吗?
错误:java.lang.RuntimeException:无法启动活动 ComponentInfo{com.example.terik.thirdtry/com.example.terik.threetry.MainActivity}: android.view.InflateException: 二进制 XML 文件行 #23: 膨胀类 android.widget.Button 时出错
这是 xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.terik.thirdattempt" >
<uses-sdk android:minSdkVersion="8" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<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>
</application>
</manifest>
这是我踢腿和咯咯笑的布局。
<TextView android:layout_width="500dp"
android:layout_height="200dp"
android:text="0"
android:textSize="72pt"
android:id="@+id/textView"
android:layout_alignParentTop="true"
android:layout_alignLeft="@+id/Button1"
android:layout_alignStart="@+id/Button1"
android:layout_marginLeft="41dp"
android:layout_marginStart="71dp"
android:layout_alignRight="@+id/Button1"
android:layout_alignEnd="@+id/Button1"></TextView>
<Button
android:layout_width="200dp"
android:layout_height="200dp"
android:id="@+id/Button1"
android:background="@drawable/custom_button"
android:adjustViewBounds="false"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="51dp" />
</RelativeLayout>
我猜我的主活动.java文件
package com.example.terik.thirdattempt;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;
public class MainActivity extends ActionBarActivity {
int number = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView=(TextView)findViewById(R.id.textView);
}
@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);
}
public void addOne(View view){
number = number +1;
textView.setText(number);
}
}
您得到空指针异常,因为您在设置内容视图之前声明了文本视图。这应该可以解决这个问题(但我不明白 addOne 是什么方法,所以我不理会它):
int number = 0;
TextView textView;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView)findViewById(R.id.textView);
}
@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);
}
public void addOne(View view){
number = number +1;
textView.setText(number);
}
您可以在 onCreate 函数中的 setContentView(R.layout.activity_main) 之后初始化 UI。
因此,您的应用程序在启动设备时崩溃了。您应该在onCreate函数之后初始化TextView,如下所示:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView)findViewById(R.id.textView);
}