如何在工具栏上的后退箭头上显示和设置单击事件

Question

如何在android工具栏中设置后退箭头并应用单击监听器？

Answer 1

先做一个 toolbar.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:local="http://schemas.android.com/apk/res-auto"
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minHeight="?attr/actionBarSize"
    android:background="@color/colorPrimary"
    local:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
    local:popupTheme="@style/ThemeOverlay.AppCompat.Light" />

然后activity_main.xml像这样包含它:

<LinearLayout
    android:id="@+id/container_toolbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <include
        android:id="@+id/toolbar"
        layout="@layout/toolbar" />

</LinearLayout>

然后在你的MainActivity.java文件中,把这段代码:

mToolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(mToolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);
getSupportActionBar().setTitle("MyTitle");

要在背面添加侦听器,请使用以下方法:

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case android.R.id.home:
            // todo: goto back activity from here

            Intent intent = new Intent(CurrentActivity.this, MainActivity.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(intent);
            finish();
            return true;

        default:
            return super.onOptionsItemSelected(item);
    }
}

Answer 2

Toolbar mToolbar= (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(mToolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);    
mToolbar.setNavigationOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        // perform whatever you want on back arrow click 
    }
});

//使用lamda表达式

toolbar.setNavigationOnClickListener(view -> onBackPressed());

Answer 3

如果你使用默认的Android后退按钮

getSupportActionBar().setDisplayHomeAsUpEnabled(true);

然后覆盖onOptionsItemSelected之类的

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case android.R.id.home:
            //do whatever
            return true;
        default:
           return super.onOptionsItemSelected(item);
    }
}

Answer 4

完整的例子在这里 http://www.freakyjolly.com/how-to-add-back-arrow-in-android-activity/

使用要在其上显示后退图标的getSupportActionBar() Activity

在OtherActivity.class 中

public class OtherActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.other_activity);


    ActionBar actionBar = getSupportActionBar();
    if (actionBar != null) {
        actionBar.setDisplayHomeAsUpEnabled(true);
    }
}

public boolean onOptionsItemSelected(MenuItem item){
    switch (item.getItemId()) {
        case android.R.id.home:
            finish();
            return true;
    }
    return super.onOptionsItemSelected(item);
}

public boolean onCreateOptionsMenu(Menu menu) {
    return true;
}

}

这将添加一个事件监听

Answer 5

如果您想知道何时单击主页是AppCompatActivity，则应尝试如下操作：使用此代码：

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);

像往常一样监听android.R.id.home上的点击事件：

@Override
public boolean onOptionsItemSelected(MenuItem menuItem) {
    if (menuItem.getItemId() == android.R.id.home) {
         Intent intent = new Intent(CurrentActivity.this, MainActivity.class);
         startActivity(intent);
         finish();
    }
    return super.onOptionsItemSelected(menuItem);
}