1)Fragment什么时候初始化和add到容器中？
2)Fragment什么时候hide和show？
3)如何让TextView被选中？选中一个TextView后，要做一些什么操作？
4)刚进入MainActivity怎么样让一个TextView处于Selected的状态？
1)+2)我们选中TextView后对对应的Fragment进行判空，如果为空，初始化，并添加到容器中； 而hide的话，我们定义一个方法hide所有的Fragment，每次触发点击事件就先调用这个hideAll方法， 讲所有Fragment隐藏起来，然后如果TextView对应的Fragment不为空，我们就将这个Fragment显示出来；
3)这个我们通过点击事件来实现，点击TextView后先重置所有TextView的选中状态为false，然后设置点击的 TextView的选中状态为true；
4)我们是通过点击事件来设置选中的，那么在onCreate()方法里加个触发点击事件的方法模拟点击就可以了~ txt_channel.performClick();
Code
BottomNvgWithTextView.java
package com.turing.base.activity.fragment.fragmentPractice1;
import android.os.Bundle;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.TextView;
import com.turing.base.R;
public class BottomNvgWithTextView extends AppCompatActivity implements View.OnClickListener {
//UI Object
private TextView txt_topbar;
private TextView txt_channel;
private TextView txt_message;
private TextView txt_better;
private TextView txt_setting;
private FrameLayout ly_content;
//Fragment Object
private Fragment_btm_nvg_tv_context fg1, fg2, fg3, fg4;
private FragmentManager fManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_fragment__bottom_nvg_with_text_view);
fManager = getSupportFragmentManager();
bindViews();
//模拟一次点击，既进去后选择第一项
txt_channel.performClick();
}
/**
* UI组件初始化与事件绑定
*/
private void bindViews() {
txt_topbar = (TextView) findViewById(R.id.txt_topbar);
txt_channel = (TextView) findViewById(R.id.txt_channel);
txt_message = (TextView) findViewById(R.id.txt_message);
txt_better = (TextView) findViewById(R.id.txt_better);
txt_setting = (TextView) findViewById(R.id.txt_setting);
ly_content = (FrameLayout) findViewById(R.id.ly_content);
txt_channel.setOnClickListener(this);
txt_message.setOnClickListener(this);
txt_better.setOnClickListener(this);
txt_setting.setOnClickListener(this);
}
/**
* 重置所有文本的选中状态
*/
private void setSelected() {
txt_channel.setSelected(false);
txt_message.setSelected(false);
txt_better.setSelected(false);
txt_setting.setSelected(false);
}
/**
* 隐藏所有Fragment
*/
private void hideAllFragment(FragmentTransaction fragmentTransaction) {
if (fg1 != null) fragmentTransaction.hide(fg1);
if (fg2 != null) fragmentTransaction.hide(fg2);
if (fg3 != null) fragmentTransaction.hide(fg3);
if (fg4 != null) fragmentTransaction.hide(fg4);
}
@Override
public void onClick(View v) {
FragmentTransaction fTransaction = fManager.beginTransaction();
hideAllFragment(fTransaction);
switch (v.getId()) {
case R.id.txt_channel:
setSelected();
txt_channel.setSelected(true);
if (fg1 == null) {
fg1 = new Fragment_btm_nvg_tv_context("第一个Fragment");
fTransaction.add(R.id.ly_content, fg1);
} else {
fTransaction.show(fg1);
}
break;
case R.id.txt_message:
setSelected();
txt_message.setSelected(true);
if (fg2 == null) {
fg2 = new Fragment_btm_nvg_tv_context("第二个Fragment");
fTransaction.add(R.id.ly_content, fg2);
} else {
fTransaction.show(fg2);
}
break;
case R.id.txt_better:
setSelected();
txt_better.setSelected(true);
if (fg3 == null) {
fg3 = new Fragment_btm_nvg_tv_context("第三个Fragment");
fTransaction.add(R.id.ly_content, fg3);
} else {
fTransaction.show(fg3);
}
break;
case R.id.txt_setting:
setSelected();
txt_setting.setSelected(true);
if (fg4 == null) {
fg4 = new Fragment_btm_nvg_tv_context("第四个Fragment");
fTransaction.add(R.id.ly_content, fg4);
} else {
fTransaction.show(fg4);
}
break;
}
fTransaction.commit();
}
}
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