Android复习代码1-4章

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public class RudioButton extends AppCompatActivity {@Overrideprotected void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_rudio_button);// 找到RadioGroup和TextView的实例RadioGroup radioGroup = findViewById(R.id.radio);TextView tv = findViewById(R.id.tv);// 在radioGroup实例上设置监听器radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {@Overridepublic void onCheckedChanged(RadioGroup group, int checkedId) {if (checkedId == R.id.girl) {tv.setText("女生");} else {tv.setText("男生");}}});}
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"><RadioGroupandroid:layout_width="match_parent"android:layout_height="wrap_content"android:id="@+id/radio"><RadioButtonandroid:id="@+id/girl"android:layout_width="match_parent"android:layout_height="wrap_content"android:text="女"/><RadioButtonandroid:layout_width="match_parent"android:layout_height="wrap_content"android:text="男"/></RadioGroup><TextViewandroid:layout_width="wrap_content"android:layout_height="match_parent"android:textSize="20sp"android:id="@+id/tv"/></LinearLayout>

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<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"><CheckBoxandroid:id="@+id/badminton"android:layout_width="match_parent"android:layout_height="wrap_content"android:text="羽毛球"/><CheckBoxandroid:layout_width="match_parent"android:layout_height="wrap_content"android:id="@+id/basketball"android:text="篮球"/><CheckBoxandroid:layout_width="match_parent"android:layout_height="wrap_content"android:id="@+id/pingpang"android:text="乒乓"/><TextViewandroid:layout_width="match_parent"android:layout_height="wrap_content"android:id="@+id/hobby"android:textSize="30sp"/>
</LinearLayout>

package com.example.bok;import android.os.Bundle;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.TextView;import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;public class hobby extends AppCompatActivity implements CompoundButton.OnCheckedChangeListener {private TextView hobby;private String hobbys ;@Overrideprotected void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.checkbox);CheckBox checkBox1 = findViewById(R.id.badminton);CheckBox checkBox2 =findViewById(R.id.basketball);CheckBox checkBox3 =findViewById(R.id.pingpang);checkBox1.setOnCheckedChangeListener(this);checkBox2.setOnCheckedChangeListener(this);checkBox3.setOnCheckedChangeListener(this);hobby=findViewById(R.id.hobby);hobbys = new String();}@Overridepublic void onCheckedChanged(CompoundButton compoundButton, boolean b) {String motion = compoundButton.getText().toString();if (b){if(!hobbys.contains(motion)){hobbys=hobbys+motion;hobby.setText(hobbys);}}else {if(hobbys.contains(motion)){hobbys=hobbys.replace(motion,"");hobby.setText(hobbys);}}}}

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 AndroidManifest.xml中注册Activity启动和关闭activity

    @Overridepublic void onClick(View view) {Intent intent =new Intent(MainActivity.this, jump.class);startActivity(intent);}

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 发数据

   public void onClick(View view) {String acc =id.getText().toString();String psd =psw.getText().toString();Intent intent =new Intent(MainActivity.this, jump.class);intent.putExtra("username",acc);intent.putExtra("psw",psd);startActivity(intent);}

接收

public class jump extends AppCompatActivity {@Overrideprotected void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.jump);Button btn2 = findViewById(R.id.btn2);Intent intent = this.getIntent();String username= intent.getStringExtra("username");String psw = intent.getStringExtra("psw");TextView tv1 = findViewById(R.id.tv1);TextView tv2 = findViewById(R.id.tv2);tv1.setText(username);tv2.setText(psw);btn2.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {finish();}});}
}

    @Overridepublic void onClick(View view) {String acc =id.getText().toString();String psd =psw.getText().toString();Bundle bundle = new Bundle();bundle.putString("username",acc);bundle.putString("psw",psd);Intent intent =new Intent(MainActivity.this, jump.class);intent.putExtras(bundle);startActivity(intent);}

        Button btn2 = findViewById(R.id.btn2);Bundle bundle = this.getIntent().getExtras();String username= bundle.getString("username");String psw = bundle.getString("psw");

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public class FR extends Fragment {@Nullable@Overridepublic View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {View v = inflater.inflate(R.layout.activity_main,container,false);return v;}
}