如何在应用程序标题旁边有一个后退按钮？

Question

如何在应用标题旁边添加后退按钮？

  public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.information);
        ActionBar actionBar = getSupportActionBar();
        actionBar.setDisplayHomeAsUpEnabled(true);
}

  @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        MenuInflater inflater=getMenuInflater();
        inflater.inflate(R.menu.create_back, 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.
        switch(item.getItemId()) {
            case R.id.back: // back to previous activity
                this.finish();
                return true;
        }
        return super.onOptionsItemSelected(item);
    }

后退按钮显示在右侧hand-side。 如何将其移动到left-hand一侧？

create-back

<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto">

<item
    android:icon="@mipmap/back_to"
    android:id="@+id/back"
    android:orderInCategory="100"
    android:title="Back"
    app:showAsAction="always" />
    </menu>

I can create a back icon, just don't know how to move it to left-hand side.

Answer 1

在 Activity

的 oncreate() 中使用以下代码

ActionBar ab = getActionBar();
ab.setHomeButtonEnabled(true);
ab.setDisplayHomeAsUpEnabled(true);

并添加动作

@Override
public boolean onMenuItemSelected(int featureId, MenuItem item) {

    int itemId = item.getItemId();
    switch (itemId) {
    case android.R.id.home:
        onBackPressed();

        Toast.makeText(this, "home pressed", Toast.LENGTH_LONG).show();
        break;

    }

    return true;
}

Answer 2

将大小写 R.id.back: 更改为 大小写 R.id.home: .

你的问题已经解决了。

已更新

使用此代码获取左侧的图标，

final ActionBar actionBar = getSupportActionBar();
        actionBar.setDisplayHomeAsUpEnabled(true);
        actionBar.setHomeAsUpIndicator(R.drawable.back_dark);


 @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.
            switch(item.getItemId()) {
                case R.id.home: // back to previous activity
                    onBackPressed();
                    return true;
            }
            return super.onOptionsItemSelected(item);
        }

Answer 3

为了使图标正常工作，只需添加此

@Override
    public boolean onOptionsItemSelected(MenuItem item) {
        onBackPressed();
        return true;
    }

而不是

@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.
            switch(item.getItemId()) {
                case R.id.home: // back to previous activity
                    onBackPressed();
                    return true;
            }
            return super.onOptionsItemSelected(item);
        }

如何在应用程序标题旁边有一个后退按钮？

How to have a back button beside the app title?

android

android-layout

android-studio

android-actionbar

back