Intent机制 Activity间数据传递

双向传递数据

A启动B，B使用setResut()方法将Intent结果传到A的onActivityResult中。

B返回数据给A的核心代码框架

A端

Intent intent=new Intent(MainActivity.this,B_Activity.class);
startActivityForResult(intent,100);

B端

Intent intent=getIntent();
Bundle bundle=intent.getExtras();
intent.putExtras(bundle);
setResult(RESULT_OK,intent);
finish();

双向传递数据示例

MainActivity输入两个整数并选择需要进行的计算，B_Activity计算并返回值。

MainActivity主要代码

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button btn1=(Button)findViewById(R.id.rbtn_1);
        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                EditText et1=(EditText)findViewById(R.id.editText1);
                EditText et2=(EditText)findViewById(R.id.editText2);
                String a=et1.getText().toString();
                String b=et2.getText().toString();
                Intent intent=new Intent(MainActivity.this,B_Activity.class);
                Bundle bundle=new Bundle();
                bundle.putString("a",a);
                bundle.putString("b",b);
                intent.putExtras(bundle);
                startActivityForResult(intent,100);

            }
        });

        Button btn2=(Button)findViewById(R.id.rbtn_2);
        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                EditText et1=(EditText)findViewById(R.id.editText1);
                EditText et2=(EditText)findViewById(R.id.editText2);
                String a=et1.getText().toString();
                String b=et2.getText().toString();
                Intent intent=new Intent(MainActivity.this,B_Activity.class);
                Bundle bundle=new Bundle();
                bundle.putString("a",a);
                bundle.putString("b",b);
                intent.putExtras(bundle);
                startActivityForResult(intent,200);

            }
        });

        Button btn3=(Button)findViewById(R.id.rbtn_3);
        btn3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                EditText et1=(EditText)findViewById(R.id.editText1);
                EditText et2=(EditText)findViewById(R.id.editText2);
                String a=et1.getText().toString();
                String b=et2.getText().toString();
                Intent intent=new Intent(MainActivity.this,B_Activity.class);
                Bundle bundle=new Bundle();
                bundle.putString("a",a);
                bundle.putString("b",b);
                intent.putExtras(bundle);
                startActivityForResult(intent,300);

            }
        });

        Button btn4=(Button)findViewById(R.id.rbtn_4);
        btn4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                EditText et1=(EditText)findViewById(R.id.editText1);
                EditText et2=(EditText)findViewById(R.id.editText2);
                String a=et1.getText().toString();
                String b=et2.getText().toString();
                Intent intent=new Intent(MainActivity.this,B_Activity.class);
                Bundle bundle=new Bundle();
                bundle.putString("a",a);
                bundle.putString("b",b);
                intent.putExtras(bundle);
                startActivityForResult(intent,400);

            }
        });


    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(requestCode==100)
            if(resultCode==RESULT_OK){
                Bundle bundle=data.getExtras();
                int s=bundle.getInt("sum");
                TextView tv=(TextView)findViewById(R.id.msg);;
                tv.setText("结果="+s);
            }
        if(requestCode==200)
            if(resultCode==RESULT_OK){
                Bundle bundle=data.getExtras();
                int s=bundle.getInt("sum2");
                TextView tv=(TextView)findViewById(R.id.msg);;
                tv.setText("结果="+s);
            }
        if(requestCode==300)
            if(resultCode==RESULT_OK){
                Bundle bundle=data.getExtras();
                int s=bundle.getInt("sum3");
                TextView tv=(TextView)findViewById(R.id.msg);;
                tv.setText("结果="+s);
            }
        if(requestCode==400)
            if(resultCode==RESULT_OK){
                Bundle bundle=data.getExtras();
                int s=bundle.getInt("sum4");
                TextView tv=(TextView)findViewById(R.id.msg);;
                tv.setText("结果="+s);
            }
    }
}

B_Activity主要代码

public class B_Activity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_b_);
        Intent intent=getIntent();
        Bundle bundle=intent.getExtras();

        String a=bundle.getString("a");
        String b=bundle.getString("b");


        int sum=Integer.parseInt(a)+Integer.parseInt(b);
        bundle.putInt("sum",sum);
        intent.putExtras(bundle);

        int sum2=Integer.parseInt(a)-Integer.parseInt(b);
        bundle.putInt("sum2",sum2);
        intent.putExtras(bundle);

        int sum3=Integer.parseInt(a)*Integer.parseInt(b);
        bundle.putInt("sum3",sum3);
        intent.putExtras(bundle);

        int sum4=Integer.parseInt(a)/Integer.parseInt(b);
        bundle.putInt("sum4",sum4);
        intent.putExtras(bundle);

        setResult(RESULT_OK,intent);

        finish();
    }
}

activity_main.xml布局文件

<LinearLayout
        android:id="@+id/LayOut1"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="8dp"
        android:orientation="horizontal"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <TextView
            android:id="@+id/tv1"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_weight="0"
            android:text="a="
            android:textSize="30sp" />

        <EditText
            android:id="@+id/editText1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="0"
            android:ems="10"
            android:inputType="numberSigned" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/LayOut2"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_marginStart="8dp"
        android:layout_marginEnd="8dp"
        android:orientation="horizontal"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/LayOut1">

        <TextView
            android:id="@+id/tv2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="0"
            android:text="b="
            android:textSize="30sp" />

        <EditText
            android:id="@+id/editText2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="0"
            android:ems="10"
            android:inputType="numberSigned" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/LayOut3"
        android:layout_width="match_parent"
        android:layout_height="100dp"
        android:layout_marginStart="8dp"
        android:layout_marginEnd="8dp"
        android:orientation="vertical"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/LayOut2">

        <RadioGroup
            android:id="@+id/RadioButton1"
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:orientation="horizontal">

            <RadioButton
                android:id="@+id/rbtn_1"
                android:layout_width="74dp"
                android:layout_height="50dp"
                android:text="+"
                android:textSize="30sp" />

            <RadioButton
                android:id="@+id/rbtn_2"
                android:layout_width="78dp"
                android:layout_height="wrap_content"
                android:text="-"
                android:textSize="36sp" />

            <RadioButton
                android:id="@+id/rbtn_3"
                android:layout_width="73dp"
                android:layout_height="50dp"
                android:layout_weight="0"
                android:text="*"
                android:textSize="36sp" />

            <RadioButton
                android:id="@+id/rbtn_4"
                android:layout_width="69dp"
                android:layout_height="wrap_content"
                android:layout_weight="0"
                android:text="/"
                android:textSize="36sp" />
        </RadioGroup>

        <TextView
            android:id="@+id/msg"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:text="结果="
            android:textSize="30sp" />
    </LinearLayout>