标题栏显示返回按钮

backTitle.java

package com.toby.personal.myapplication;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;

public class MainActivity extends AppCompatActivity {

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

        android.support.v7.app.ActionBar actionBar = getSupportActionBar();
        if(actionBar != null){
            actionBar.setHomeButtonEnabled(true);
            actionBar.setDisplayHomeAsUpEnabled(true);
        }
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                this.finish(); // back button
                return true;
        }
        return super.onOptionsItemSelected(item);
    }

}

//作者：赵者也
//链接：https://www.jianshu.com/p/3600b2178afa