添加

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

private Button bu_delete;

private Button bu_01;

private Button bu_02;

private Button bu_03;

private Frag1 frag1;

private Frag2 frag2;

private Frag3 frag3;

private ViewPager vp;

private FragmentManager manager;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

initView();

}

private void initView() {

bu_delete = (Button) findViewById(R.id.bu_delete);

bu_01 = (Button) findViewById(R.id.bu_01);

bu_02 = (Button) findViewById(R.id.bu_02);

bu_03 = (Button) findViewById(R.id.bu_03);

bu_01.setOnClickListener(this);

bu_02.setOnClickListener(this);

bu_03.setOnClickListener(this);

frag1 = new Frag1();

frag2 = new Frag2();

frag3 = new Frag3();

//清除缓存的监听

bu_delete.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

ImageLoader.getInstance().clearMemoryCache();

ImageLoader.getInstance().clearDiskCache();

}

});

manager = getSupportFragmentManager();

FragmentTransaction transaction = manager.beginTransaction();

transaction.add(R.id.frame, frag1);

transaction.add(R.id.frame, frag2);

transaction.add(R.id.frame, frag3);

showOrHide(frag1, frag2, frag3);

transaction.commit();

}

//fragment的显示与隐藏

private void showOrHide(Fragment from, Fragment to1, Fragment to2) {

FragmentTransaction transaction = manager.beginTransaction();

transaction.show(from);

transaction.hide(to1);

transaction.hide(to2);

transaction.commit();

}

@Override

public void onClick(View v) {

switch (v.getId()) {

case R.id.bu_01:

showOrHide(frag1, frag2, frag3);

break;

case R.id.bu_02:

showOrHide(frag2, frag1, frag3);

break;

case R.id.bu_03:

showOrHide(frag3, frag1, frag2);

break;

}

}

}