Andriod studio学习 之 fragment高级进阶
第5天Fragment高级进阶
Fragment 回退栈
radioGroupId.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
switch (checkedId) {
case R.id.person_id:
manager = getSupportFragmentManager();
fragmentTransaction = manager.beginTransaction();
// fragmentTransaction.replace(R.id.frame_layout_id,new FristFragment());
fragmentTransaction.add(R.id.frame_layout_id,new FristFragment());
//入栈
fragmentTransaction.addToBackStack("11");
fragmentTransaction.commit();
break;
case R.id.message_id:
manager = getSupportFragmentManager();
//出栈
manager.popBackStack();
SelectActivity.this.fragmentTransaction = manager.beginTransaction();
SelectActivity.this.fragmentTransaction.replace(R.id.frame_layout_id,new SecondFragment());
// fragmentTransaction.addToBackStack(null);
SelectActivity.this.fragmentTransaction.commit();
break;
default:
break;
}
}
});
case R.id.message_id:
manager = getSupportFragmentManager();
// manager.popBackStack();
fragmentTransaction = manager.beginTransaction();
fragmentTransaction.replace(R.id.frame_layout_id,new SecondFragment());
//添加了返回栈,点击back的时候,不会退出activity,而会返回到之前的fragment界面.
// fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
break;
Fragment 传值介绍
activity 给 fragment传值
主要涉及到一个方法是getArguments()和setArguments().
一个设置属性值,一个去取属性值.
步骤：
要传的值，放到bundle对象里；
在Activity中创建该Fragment的对象fragment，通过调用
fragment.setArguments()传递到fragment中；
然后更新fragment.
在该Fragment中通过调用getArguments()得到bundle对象，就能得到里面的值。
代码来了 这是刚创建完成的activity
package com.example.day004;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
/**
* activity 向 fragment 传值
*/
public class A2FActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_a_2_f);
}
//点击事件的方法
public void click(View view) {
}
}
这是修完以后的他的xml的布局文件
创建fragment(右键一键完事,带布局)
package com.example.day004.fragment;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.example.day004.R;
/**
*用来接受传值的
*/
public class ShowContextFragment extends Fragment {
public ShowContextFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_show_context, container, false);
}
}
修改后的fragment的xml布局文件
完整版的fragment
package com.example.day004.fragment;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.example.day004.R;
/**
*用来接受传值的
*/
public class ShowContextFragment extends Fragment {
private TextView textView;
public ShowContextFragment() {
// Required empty public constructor
}
//现在text里面的值是"hello_blank_fragment",思路就是拿到控件,重新赋值即可.
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View inflate = inflater.inflate(R.layout.fragment_show_context, container, false);
//1 拿控件
textView = inflate.findViewById(R.id.context_tv_id);
//2 给控件赋值
Bundle arguments = getArguments();
if(arguments != null){ //第一次启动一定为null,所以要判断一下
String key = arguments.getString("key");
textView.setText(key);
}
return inflate;
}
}
完整版的a2fActivity
package com.example.day004;
import android.icu.util.BuddhistCalendar;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import com.example.day004.fragment.ShowContextFragment;
import java.io.BufferedReader;
/**
* activity 向 fragment 传值
*/
public class A2FActivity extends AppCompatActivity {
private FragmentManager fragmentManager;
private FragmentTransaction fragmentTransaction;
private EditText editText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_a_2_f);
//0,取到edit的控件和值
editText = findViewById(R.id.et_id);
//1,在这里动态添加一个fragment
fragmentManager = getSupportFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
//注意这个布局文件,是R.layout.activity_a_2_f xml文件里的线性布局
fragmentTransaction.add(R.id.linear_layout_id,new ShowContextFragment());
fragmentTransaction.commit();
}
public void click(View view) {
//取到输入的值
String string = editText.getText().toString();
//创建fragment对象
ShowContextFragment showContextFragment = new ShowContextFragment();
//创建bundle
Bundle bundle = new Bundle();
bundle.putString("key",string);
//给fragment对象赋值
showContextFragment.setArguments(bundle);
//动态修改fragment
fragmentManager = getSupportFragmentManager();
fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.linear_layout_id,showContextFragment);
fragmentTransaction.commit();
}
}
fragment 给 activity传值
第一种：
在Activity中调用getFragmentManager()得到fragmentManager,，调用findFragmentByTag(tag)或者通过findFragmentById(id)
FragmentManager fragmentManager = getFragmentManager()；
Fragment fragment = fragmentManager.findFragmentByTag(tag)；
第二种：
通过回调的方式，定义一个接口（可以在Fragment类中定义），接口中有一个空的方法，在fragment中需要的时候调用接口的方法，值可以作为参数放在这个方法中，然后让Activity实现这个接口，必然会重写这个方法，这样值就传到了Activity中.
大白话,就是java的父类引用指向了子类对象
Activity中的代码
package com.example.day004;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;
import com.example.day004.fragment.ShowTitleFragment;
public class F2AActivity extends AppCompatActivity implements ShowTitleFragment.MyListener {
private TextView textView;
@Override
public void sendMessage(String string) {
textView.setText(string);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_f_2_a);
textView = findViewById(R.id.f2a_tv_id);
}
}
Activity中的xml文件
fragment中的代码
package com.example.day004.fragment;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import com.example.day004.R;
/**
* A simple {@link Fragment} subclass.
*/
public class ShowTitleFragment extends Fragment {
private EditText editText;
private Button button;
private MyListener listener;
public ShowTitleFragment() {
// Required empty public constructor
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
//拿到与当前fragment关联的Activity.
listener = (MyListener) getActivity();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View inflate = inflater.inflate(R.layout.fragment_show_title, container, false);
//取到所有控件
editText = inflate.findViewById(R.id.fm_title_et_id);
button = inflate.findViewById(R.id.fm_title_button_id);
//点击事件
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String string = editText.getText().toString();
if(string != null){
//注意了.这里是父类引用指向了子类对象,其实是activity中的sendmessage方法在执行.
listener.sendMessage(string);
}
}
});
//返回fragment中的布局视图
return inflate;
}
//自定义的接口
public interface MyListener{
void sendMessage(String string);
}
}
fragment的xml文件
fragment 给 fragment 传值
第一种：
动态创建的fragment通过findFragmentByTag得到另一个的Fragment的对象，这样就可以调用另一个的方法了。
静态创建的fragment通过findFragmentById得到另一个的Fragment的对象，这样就可以调用另一个的方法了。
package com.example.day005.fragment;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import com.example.day005.R;
/**
* A simple {@link Fragment} subclass.
*/
public class LeftFragment extends Fragment {
private EditText editText;
private Button send_button;
public LeftFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View inflate = inflater.inflate(R.layout.fragment_left, container, false);
editText = inflate.findViewById(R.id.left_textView_id);
send_button = inflate.findViewById(R.id.left_button_id);
send_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String string = editText.getText().toString();
**了解一种即可,不重点**
//1 fragment传值方式1
// 通过id找的指定fragment,调用他的方法,给他的组件赋值.
FragmentManager fragmentManager = getFragmentManager(); //注意,这个manager是v4包下的.
RightFragment rightFragment=(RightFragment) fragmentManager.findFragmentById(R.id.right_fragment_id);
rightFragment.setTextView(string);
//2 通过id找的指定fragment,得到他所有的view.在通过findViewById 找到组件.赋值
TextView textView = getFragmentManager().findFragmentById(R.id.right_fragment_id).getView().findViewById(R.id.right_textview_id);
textView.setText(string);
//3
//因为两个fragment在一个activity里面,所有可以通过拿到activity里面所有的指定组件.
TextView textView = (TextView) getActivity().findViewById(R.id.right_textview_id);
textView.setText(string);
}
});
return inflate;
}
}
第二种(重点)
通过接口回调的方式。
与上面的接口回调用法相同
第三种：
通过setArguments，getArguments的方式。
fragment 多层嵌套
与正常使用区别不大
FragmentManager childFragmentManager = getChildFragmentManager();
FragmentTransaction fragmentTransaction = childFragmentManager.beginTransaction();
fragmentTransaction.add(R.id.left_fragment_id,new RightFragment());
fragmentTransaction.commit();
案例(微信底部按钮与fragment实现界面切换)
activity中的代码
package com.example.day004.activities;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.FrameLayout;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;
import com.example.day004.R;
import com.example.day004.fragment.FristFragment;
import com.example.day004.fragment.SecondFragment;
/**
* 底部导航
*/
public class SelectActivity extends AppCompatActivity {
private FrameLayout frameLayoutId;
private RadioGroup radioGroupId;
private RadioButton personId;
private RadioButton messageId;
private static final String TAG = "SelectActivity";
private FragmentManager manager;
private FragmentTransaction fragmentTransaction;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_select);
frameLayoutId = findViewById(R.id.frame_layout_id);
radioGroupId = findViewById(R.id.radio_group_id);
radioGroupId.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
switch (checkedId) {
case R.id.person_id:
manager = getSupportFragmentManager();
fragmentTransaction = manager.beginTransaction();
// fragmentTransaction.replace(R.id.frame_layout_id,new FristFragment());
fragmentTransaction.add(R.id.frame_layout_id,new FristFragment());
fragmentTransaction.addToBackStack("11");
Log.i(TAG, "onCheckedChanged: "+SelectActivity.class.getName());
fragmentTransaction.commit();
break;
case R.id.message_id:
manager = getSupportFragmentManager();
manager.popBackStack();
SelectActivity.this.fragmentTransaction = manager.beginTransaction();
SelectActivity.this.fragmentTransaction.replace(R.id.frame_layout_id,new SecondFragment());
// fragmentTransaction.addToBackStack(null);
SelectActivity.this.fragmentTransaction.commit();
break;
default:
break;
}
}
});
}
}
activity的xml
说明
android:drawableTop="@drawable/select_message"
android:textColor="@drawable/select_text"
这两个属性,参照下面链接创建
https://blog.csdn.net/qq_34178710/article/details/91411003
java代码中的fragment,右键创建即可.