526互联

fragment增删查替

发布时间 2023-04-10 00:01:58作者: 实名吓我一跳

一：增加

第一种方式：最常用方式

public void addFragment1(View view) {
    FragmentManager supportFragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
    fragmentTransaction.add(R.id.fcv, DynamicFragment.class,null).setReorderingAllowed(true).commit();
}

第二种方式：推入栈，但出来比较麻烦，因为替换后，还得一个一个消除，在后台

public void addFragment2(View view) {
    FragmentManager supportFragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
    fragmentTransaction.add(R.id.fcv, DynamicFragment.class,null)
            .addToBackStack("myBackStack")
            .setReorderingAllowed(true)
            .commit();
}

第三种方式：定义一个对象

public void addFragment3(View view) {
    FragmentManager supportFragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
    DynamicFragment dynamicFragment = new DynamicFragment();
    fragmentTransaction.add(R.id.fcv,dynamicFragment)
            .setReorderingAllowed(true)
            .commit();
}

二：清除

public void removeFragment(View view) {
    FragmentManager supportFragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
    Fragment fragment = supportFragmentManager.findFragmentById(R.id.fcv);
    if(fragment != null)
    {
        Toast.makeText(this, "找到了,消除", Toast.LENGTH_SHORT).show();
        fragmentTransaction.remove(fragment).commit();
    }
    else
    {
        Toast.makeText(this, "没有找到", Toast.LENGTH_SHORT).show();
    }
}

三：查找

通过id查找（还有tag)

public void findFragmentById(View view) {
        FragmentManager supportFragmentManager = getSupportFragmentManager();
        Fragment fragment = supportFragmentManager.findFragmentById(R.id.fcv);
        if(fragment != null)
        {
            Toast.makeText(this, "找到了", Toast.LENGTH_SHORT).show();
        }
        else
        {
            Toast.makeText(this, "没有找到", Toast.LENGTH_SHORT).show();
        }
//        FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
    }

四：替换

public void replaceFragment(View view) {
    FragmentManager supportFragmentManager = getSupportFragmentManager();
    FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
    DynamicFragment dynamicFragment = new DynamicFragment();
    fragmentTransaction.replace(R.id.fcv,dynamicFragment).commit();
}
全部代码：
public class FragmentModifyActivity extends AppCompatActivity {

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

    public void addFragment1(View view) {
        FragmentManager supportFragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.fcv, DynamicFragment.class,null).commit();
    }

    public void addFragment2(View view) {
        FragmentManager supportFragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.fcv, DynamicFragment.class,null)
                .addToBackStack("myBackStack")
                .setReorderingAllowed(true)
                .commit();
    }

    public void addFragment3(View view) {
        FragmentManager supportFragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
        DynamicFragment dynamicFragment = new DynamicFragment();
        fragmentTransaction.add(R.id.fcv,dynamicFragment)
                .addToBackStack("myBackStack")
                .setReorderingAllowed(true)
                .commit();
    }

    public void findFragmentById(View view) {
        FragmentManager supportFragmentManager = getSupportFragmentManager();
        Fragment fragment = supportFragmentManager.findFragmentById(R.id.fcv);
        if(fragment != null)
        {
            Toast.makeText(this, "找到了", Toast.LENGTH_SHORT).show();
        }
        else
        {
            Toast.makeText(this, "没有找到", Toast.LENGTH_SHORT).show();
        }
//        FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
    }

    public void removeFragment(View view) {
        FragmentManager supportFragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
        Fragment fragment = supportFragmentManager.findFragmentById(R.id.fcv);
        if(fragment != null)
        {
            Toast.makeText(this, "找到了,消除", Toast.LENGTH_SHORT).show();
            fragmentTransaction.remove(fragment).commit();
        }
        else
        {
            Toast.makeText(this, "没有找到", Toast.LENGTH_SHORT).show();
        }
    }

    public void replaceFragment(View view) {
        FragmentManager supportFragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = supportFragmentManager.beginTransaction();
        DynamicFragment dynamicFragment = new DynamicFragment();
        fragmentTransaction.replace(R.id.fcv,dynamicFragment).commit();
    }
}
其他和上篇一致。