我几天都在努力寻找解决方案，这让我感到疯狂。我目前正在关注http://developer.android.com/guide/topics/ui/actionbar.html#ActionItems
中的教程不幸的是，当按下SEND按钮时应用程序崩溃（在执行操作栏之前工作正常）
以下是涉及的文件：
1. AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.mycompany.myfirstapps" >
<uses-sdk android:minSdkVersion="7"
android:targetSdkVersion="18" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/Theme.AppCompat.Light.DarkActionBar">
<!-- parent activity-->
<activity
android:name=".MyActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<!--second activity -->
<activity
android:name=".DisplayMessageActivity"
android:label="@string/title_activity_display_message"
android:parentActivityName=".MyActivity" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value=".MyActivity" />
</activity>
</application>
</manifest>
package com.mycompany.myfirstapps;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.content.Intent;
import android.widget.EditText;
public class MyActivity extends AppCompatActivity {
public final static String EXTRA_MESSAGE="com.mycompany.myfirstapps.MESSAGE";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
// If your minSdkVersion is 11 or higher, instead use:
//getActionBar().setDisplayHomeAsUpEnabled(true);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu items for use in the action bar
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main_activity_actions, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle presses on the action bar items
switch (item.getItemId()) {
case R.id.action_search:
openSearch();
return true;
case R.id.action_settings:
openSettings();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
//called when user click the button
public void sendMessage(View view){
Intent intent = new Intent(this,DisplayMessageActivity.class);
EditText editText=(EditText)findViewById(R.id.edit_message);
String message=editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE,message);
startActivity(intent);
}
private void openSearch() {
//do something
}
private void openSettings() {
//do something
}
}
package com.mycompany.myfirstapps;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
public class DisplayMessageActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent= getIntent();
//create the text view
String message=intent.getStringExtra(MyActivity.EXTRA_MESSAGE);
TextView textview= new TextView(this);
textview.setTextSize(40);
textview.setText(message);
//set the text view as the activity layout
setContentView(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_display_message, 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);
}
}
<LinearLayout 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:orientation="horizontal"
android:theme="@style/CustomActionBarTheme">
<EditText
android:id="@+id/edit_message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:hint="@string/edit_message"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/button_send"
android:onClick="sendMessage"/>
</LinearLayout>
apply plugin: 'com.android.application'
android {
compileSdkVersion 22
buildToolsVersion "22.0.1"
defaultConfig {
applicationId "com.mycompany.myfirstapps"
minSdkVersion 8
targetSdkVersion 22
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:appcompat-v7:22.1.1'
}
logcat的
05-14 22:57:03.139 2514-2562/android.process.acore I/ContactLocale﹕ AddressBook Labels [en-US]: [, A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, Z, Α, Β, Γ, Δ, Ε, Ζ, Η, Θ, Ι, Κ, Λ, Μ, Ν, Ξ, Ο, Π, Ρ, Σ, Τ, Υ, Φ, Χ, Ψ, Ω, , А, Б, В, Г, Д, Ђ, Е, Є, Ж, З, И, І, Ї, Й, Ј, К, Л, Љ, М, Н, Њ, О, П, Р, С, Т, Ћ, У, Ф, Х, Ц, Ч, Џ, Ш, Щ, Ю, Я, , א, ב, ג, ד, ה, ו, ז, ח, ט, י, כ, ל, מ, נ, ס, ע, פ, צ, ק, ר, ש, ת, , ا, ب, ت, ث, ج, ح, خ, د, ذ, ر, ز, س, ش, ص, ض, ط, ظ, ع, غ, ف, ق, ك, ل, م, ن, ه, و, ي, , ก, ข, ฃ, ค, ฅ, ฆ, ง, จ, ฉ, ช, ซ, ฌ, ญ, ฎ, ฏ, ฐ, ฑ, ฒ, ณ, ด, ต, ถ, ท, ธ, น, บ, ป, ผ, ฝ, พ, ฟ, ภ, ม, ย, ร, ฤ, ล, ฦ, ว, ศ, ษ, ส, ห, ฬ, อ, ฮ, , ㄱ, ㄴ, ㄷ, ㄹ, ㅁ, ㅂ, ㅅ, ㅇ, ㅈ, ㅊ, ㅋ, ㅌ, ㅍ, ㅎ, , あ, か, さ, た, な, は, ま, や, ら, わ, #, ]
05-14 22:57:05.181 2514-2532/android.process.acore V/BackupServiceBinder﹕ doBackup() invoked
05-14 22:57:05.508 2514-2532/android.process.acore I/art﹕ WaitForGcToComplete blocked for 267.334ms for cause DisableMovingGc
05-14 22:57:05.619 2514-2532/android.process.acore E/DictionaryBackupAgent﹕ Couldn't read from the cursor
05-14 22:57:05.722 2514-2562/android.process.acore I/art﹕ WaitForGcToComplete blocked for 357.236ms for cause DisableMovingGc
05-15 01:35:32.770 2514-2525/android.process.acore W/art﹕ Suspending all threads took: 57.246ms
05-15 01:35:35.813 2514-2527/android.process.acore E/StrictMode﹕ A resource was acquired at attached stack trace but never released. See java.io.Closeable for information on avoiding resource leaks.
java.lang.Throwable: Explicit termination method 'close' not called
at dalvik.system.CloseGuard.open(CloseGuard.java:184)
at android.os.ParcelFileDescriptor.<init>(ParcelFileDescriptor.java:180)
at android.os.ParcelFileDescriptor$1.createFromParcel(ParcelFileDescriptor.java:916)
at android.os.ParcelFileDescriptor$1.createFromParcel(ParcelFileDescriptor.java:906)
at android.app.IBackupAgent$Stub.onTransact(IBackupAgent.java:57)
at android.os.Binder.execTransact(Binder.java:446)
05-15 01:35:35.925 2514-2527/android.process.acore E/StrictMode﹕ A resource was acquired at attached stack trace but never released. See java.io.Closeable for information on avoiding resource leaks.
java.lang.Throwable: Explicit termination method 'close' not called
at dalvik.system.CloseGuard.open(CloseGuard.java:184)
at android.os.ParcelFileDescriptor.<init>(ParcelFileDescriptor.java:180)
at android.os.ParcelFileDescriptor$1.createFromParcel(ParcelFileDescriptor.java:916)
at android.os.ParcelFileDescriptor$1.createFromParcel(ParcelFileDescriptor.java:906)
at android.app.IBackupAgent$Stub.onTransact(IBackupAgent.java:64)
at android.os.Binder.execTransact(Binder.java:446)
05-15 01:35:36.578 2514-2527/android.process.acore E/StrictMode﹕ A resource was acquired at attached stack trace but never released. See java.io.Closeable for information on avoiding resource leaks.
java.lang.Throwable: Explicit termination method 'close' not called
at dalvik.system.CloseGuard.open(CloseGuard.java:184)
at android.os.ParcelFileDescriptor.<init>(ParcelFileDescriptor.java:180)
at android.os.ParcelFileDescriptor$1.createFromParcel(ParcelFileDescriptor.java:916)
at android.os.ParcelFileDescriptor$1.createFromParcel(ParcelFileDescriptor.java:906)
at android.app.IBackupAgent$Stub.onTransact(IBackupAgent.java:71)
at android.os.Binder.execTransact(Binder.java:446)
可能有什么不对？
答案 0 :(得分：2)
将您的EditText移动到MyActivity.java中的onCreate（）方法
中@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
EditText editText=(EditText)findViewById(R.id.edit_message);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
// If your minSdkVersion is 11 or higher, instead use:
//getActionBar().setDisplayHomeAsUpEnabled(true);
}
在sendMessage（）方法中，只需删除该行。
编辑：您似乎正在从新的AppCompatActivity扩展。尝试在两个活动中将其更改为ActionBarActivity。例如：
public class MyActivity extends ActionBarActivity {...}
public class DisplayMessageActivity extends ActionBarActivity {...}
编辑：如果你计划不使用ActionBarActivity，那么你需要定义一个自定义工具栏并像这样初始化它。
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
答案 1 :(得分：0)
最后，我设法在挣扎了近3天后获得解决方案。解决这个问题的过程对我来说真的是一个旅程，作为Android的新手。 这是在此过程中跟踪和解决的错误和警告列表：
一旦我清除了所有弃用的问题，就会出现下一个错误：
显示java.lang.NullPointerException 我通过检查空值
解决了这个问题（或者至少我是这么认为的）断言getSupportActionBar（）！= null; getSupportActionBar（）setDisplayHomeAsUpEnabled（真）;
下一个错误总是指向sendMessage（View视图） 我发现这篇文章： java.lang.IllegalStateExeception: could not find method in activity class
它解决了我的问题。我的实际错误是我在AndroidManifest.xml中设置了主题，并再次将它们设置在布局文件中。导致应用程序崩溃。我删除了layout.xml文件中的那个。