Android的向上按钮不起作用 [英] Android Up button not working

问题描述

我想手动执行时必须发生的动作时，在动作条向上按钮pressed但由于某种原因没有任何反应，当我preSS它。

I am trying to manually implement the actions that must take place when the up button on the actionbar is pressed but for some reason nothing happens when I press it.

这是我的code：

public class ActivityOne extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_activity_one);
        Toolbar toolbar = (Toolbar)findViewById(R.id.toolbar_actionbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        Button button = (Button)findViewById(R.id.btn1);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                openActivityTwo();
            }
        });
        Button button2 = (Button)findViewById(R.id.btn2);
        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                openActivityThree();
            }
        });
    }


    void openActivityTwo(){
        Intent intent = new Intent(this, ActivityTwo.class);
        startActivity(intent);
    }

    void openActivityThree(){
        Intent intent = new Intent(this, ActivityThree.class);
        startActivity(intent);
    }


    @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_activity_one, 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;
        }

        else if(id == R.id.homeAsUp){
            Log.i("","Up is pressed");
            finish();
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

我明白，我必须明确指定父活动为活动的我想要实现了在manifest文件导航，但问题是，这种活动有多个父母，所以我想调用<当向上按钮pssed这项活动$ p $将是更好的方法code>完成（）方法。

I understand that I have to explicitly assign a parent activity for the activity I want to implement up navigation on the manifest file, but problem is that this activity has multiple parents so I thought calling the finish() method when the up button is pressed on this activity will be the better approach.

我已经尝试过两种 ID == R.id.home 和 ID == R.id.homeAsUp ，他们都不起作用。我不知道这是否是因为我使用 AppCompactActivity 还是什么请帮助

I have already tried both id == R.id.home and id == R.id.homeAsUp and they both do not work. I do not know if it is because I am using AppCompactActivity or what Please help

推荐答案

下面是如何实现这一点，试试这个code

Here is how you can implement this, try this code

使用android.R.id.home代替R.id.home或R.id.homeAsUp

public boolean onOptionsItemSelected(final MenuItem item) {

        switch (item.getItemId()) {
            case android.R.id.home:
                //use onBackPressed() OR finish();
                return true;

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

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