ActionBar 带返回箭头

activity_main.xml

<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="com.moliying.lee.actionbar.MainActivity">

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="隐藏"
android:id="@+id/button_show_hide"
android:onClick="showHideClick"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="59dp" />
</RelativeLayout>

activity_main2.xml

<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="com.moliying.lee.actionbar.Main2Activity">

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="返回第一页面"
android:id="@+id/button_back"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="198dp" />
</RelativeLayout>

res/menu 中 布局菜单

actionbar_menu.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<item android:id="@+id/save"
android:title="保存"
android:orderInCategory="100"
android:icon="@android:drawable/ic_menu_save"
app:showAsAction="always"/>
<item android:id="@+id/share"
android:title="分享"
android:orderInCategory="200"
android:icon="@android:drawable/ic_menu_share"
app:showAsAction="always"/>

<item android:id="@+id/add"
android:title="添加"
android:orderInCategory="300"
android:icon="@android:drawable/ic_menu_add"
app:showAsAction="always"/>
</menu>
search_menu.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<item android:id="@+id/search"
android:title="搜索"
android:icon="@android:drawable/ic_menu_search"
android:orderInCategory="100"
app:showAsAction="always"
app:actionViewClass=""/>

</menu>

public class MainActivity extends AppCompatActivity {
private Button button_show_hide;
private boolean flag = false;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button_show_hide = (Button) findViewById(R.id.button_show_hide);

ActionBar actionBar = getSupportActionBar();
actionBar.setDisplayShowHomeEnabled(true);
actionBar.setDisplayHomeAsUpEnabled(true);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.actionbar_menu,menu);
return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch(item.getItemId()){
case R.id.save:
Toast.makeText(MainActivity.this, "save", Toast.LENGTH_SHORT).show();
break;
case R.id.share:
Toast.makeText(MainActivity.this, "share", Toast.LENGTH_SHORT).show();
break;
case R.id.add:
Toast.makeText(MainActivity.this, "add", Toast.LENGTH_SHORT).show();
break;

case android.R.id.home:
Toast.makeText(MainActivity.this, "home", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(this,Main2Activity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);

break;
}
return super.onOptionsItemSelected(item);
}

public void showHideClick(View view) {
ActionBar actionBar = getSupportActionBar();
if(actionBar==null)return;
if(flag){
button_show_hide.setText("隐藏");
actionBar.show();
flag=false;
}else{
button_show_hide.setText("显示");
actionBar.hide();
flag=true;
}
}
}

public class Main2Activity extends AppCompatActivity implements View.OnClickListener {

private Button button_back;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);

button_back = (Button) findViewById(R.id.button_back);
button_back.setOnClickListener(this);
}

@Override
public void onClick(View v) {
switch (v.getId()){
case R.id.button_back:
Intent intent = new Intent(this,MainActivity.class);
startActivity(intent);
Toast.makeText(Main2Activity.this, "返回被点击", Toast.LENGTH_SHORT).show();
break;
}
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.search_menu,menu);
MenuItem menuItem = menu.findItem(R.id.search);
return super.onCreateOptionsMenu(menu);
}
}


带返回箭头 也可以在 清单文件中 使用<span style="color:#FF0000;"><strong>android:parentActivityName=".MainActivity"</strong></span>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.moliying.lee.actionbar">

<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".Main2Activity" <span style="color:#FF0000;"><strong>android:parentActivityName=".MainActivity"</strong></span>></activity>
</application>

</manifest>