二十六、从acticity发送信息到FragMnet
一、使用 Bundle 对象进行传递
1. activity 段中的代码
@Override public void onClick(View view) { switch (view.getId()){ case R.id.btn: Bundle bundle = new Bundle(); bundle.putString("message","使用Bundle传递"); BlankFragment1 bf = new BlankFragment1(); bf.setArguments(bundle); replaceFragment(bf); break; case R.id.btn2: replaceFragment(new ItemFragment()); break; } }
2. FragMent中的代码
@Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Bundle bundle = this.getArguments(); String str = bundle.getString("message"); Log.e("TAG", "onCreate: "+ str); if (getArguments() != null) { mParam1 = getArguments().getString(ARG_PARAM1); mParam2 = getArguments().getString(ARG_PARAM2); } }
二、Java语言中类与类字迹通信常用方案:接口
1. 创建接口
package com.example.dongtaifragment; public interface IfragmentCallback { void sendMsgToActivity(String string); String getMsgFromActivity(String msg); }
2. 页面代码
<?xml version="1.0" encoding="utf-8"?> <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context=".BlankFragment1"> <!-- TODO: Update blank fragment layout --> <TextView android:layout_width="match_parent" android:layout_height="match_parent" android:text="@string/hello_blank_fragment" /> <Button android:layout_marginTop="100dp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/btn_3" android:text="数据传递ToActivity"/> <Button android:layout_marginTop="200dp" android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/btn_4" android:text="数据传递FromActivity"/> </FrameLayout>
3. activity 段中的代码
package com.example.dongtaifragment; import androidx.appcompat.app.AppCompatActivity; import androidx.fragment.app.Fragment; import androidx.fragment.app.FragmentManager; import androidx.fragment.app.FragmentTransaction; import android.os.Binder; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.Toast; //动态添加 fragment public class MainActivity extends AppCompatActivity implements View.OnClickListener { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Button btn = findViewById(R.id.btn); btn.setOnClickListener(this); Button btn2 = findViewById(R.id.btn2); btn2.setOnClickListener(this); } @Override public void onClick(View view) { switch (view.getId()){ case R.id.btn: Bundle bundle = new Bundle(); bundle.putString("message","使用Bundle传递"); BlankFragment1 bf = new BlankFragment1(); bf.setArguments(bundle); bf.setifragmentCallback(new IfragmentCallback() { @Override public void sendMsgToActivity(String string) { Toast.makeText(MainActivity.this,string,Toast.LENGTH_SHORT).show(); } @Override public String getMsgFromActivity(String msg) { String msgs = msg; if (msg =="null"){ msgs = "Hellow,调用了MainActivity的方法 "; } return msgs; } }); replaceFragment(bf); break; case R.id.btn2: replaceFragment(new ItemFragment()); break; } } //同台切换Fragment private void replaceFragment(Fragment fragment){ FragmentManager fragmentManager = getSupportFragmentManager(); //创建一个事件 FragmentTransaction transaction = fragmentManager.beginTransaction(); //替换一个 transaction.replace(R.id.framelayouts,fragment); //将fragment添加到站中,当点击手机返回时,会返回到上一个的页面, //以值持续到回到最开始的页面,然后返回桌面 transaction.addToBackStack(null); //提交 transaction.commit(); } }
4. FragMent中的代码
package com.example.dongtaifragment; import android.os.Bundle; import androidx.fragment.app.Fragment; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.Button; import android.widget.Toast; import java.net.IDN; public class BlankFragment1 extends Fragment { private View views; private IfragmentCallback ifragmentCallback; public void setifragmentCallback( IfragmentCallback callbanck){ ifragmentCallback = callbanck; } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Bundle bundle = this.getArguments(); String str = bundle.getString("message"); Log.e("TAG", "onCreate: "+ str); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { if (views==null){ views = inflater.inflate(R.layout.fragment_blank1, container, false); } Button btn=views.findViewById(R.id.btn_3); btn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { ifragmentCallback.sendMsgToActivity("Hellow,调用了BlankFragment1的方法 "); } }); Button btn2=views.findViewById(R.id.btn_4); btn2.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { String msg = ifragmentCallback.getMsgFromActivity("null"); Toast.makeText(BlankFragment1.this.getContext(),msg,Toast.LENGTH_SHORT).show(); } }); return views; } @Override public void onResume() { super.onResume(); } }