如何在單擊按鈕時打開底部導航活動？

Question

我試圖讓我的應用程序在單擊按鈕時打開底部的導航活動。

在這里，我的主要活動有按鈕，而底部導航活動是我的第二個活動。

我的代碼中沒有顯示任何錯誤，但是每當我運行我的應用程序時，單擊按鈕就會崩潰。

試圖為開始活動做准備。

主要活動代碼：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}
private Button b1;
public void buttonOnClick(View view){
    Intent intent=new Intent(MainActivity.this,Main2Activity.class);
    startActivity(intent);
}

導航活動代碼：

public class Main2Activity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main2);
    BottomNavigationView navView = findViewById(R.id.nav_view);
    // Passing each menu ID as a set of Ids because each
    // menu should be considered as top level destinations.
    AppBarConfiguration appBarConfiguration = new AppBarConfiguration.Builder(
            R.id.navigation_home, R.id.navigation_dashboard, R.id.navigation_notifications)
            .build();
    NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
    NavigationUI.setupActionBarWithNavController(this, navController, appBarConfiguration);
    NavigationUI.setupWithNavController(navView, navController);
}

}

Answer 1

嘗試這個

public class MainActivity extends AppCompatActivity {
    private Button b1;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        b1 = findViewById(R.id.b1);
        b1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this, MainActivity2.class);
                startActivity(intent);
            }
        });
    } }

還要像這樣在AndroidManifest.xml文件中添加MainActivity和MainActivity2

<application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity2"
            android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity
            android:name=".MainActivity"
            android:screenOrientation="portrait"></activity>

    </application>