Android简单代码求和，activity跳转，跳转闪退处理

Activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:ignore="MissingConstraints">
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="第一个数字"
                android:textSize="30dp">
            </TextView>
            <EditText
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:id="@+id/x"
                android:textSize="25dp">
            </EditText>
        </LinearLayout>
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="第二个数字"
                android:textSize="30dp">
            </TextView>
            <EditText
                android:id="@+id/y"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:textSize="25dp">
            </EditText>
        </LinearLayout>
        <Button
            android:id="@+id/sub"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textSize="25dp"
            android:text="求和">
        </Button>
    </LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

Sum_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="这两个数的和为："
            android:textSize="25dp">
        </TextView>
        <TextView
            android:id="@+id/sum"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="35dp">
        </TextView>
    </LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {
    private EditText x,y;
    private Button button;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        x=(EditText) findViewById(R.id.x);
        y=(EditText) findViewById(R.id.y);
        button=(Button) findViewById(R.id.sub);
        Intent intent = new Intent(this, SumActivity.class);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                intent.putExtra("x",x.getText().toString().trim());
                intent.putExtra("y",y.getText().toString().trim());
                startActivity(intent);
            }
        });
    }
}

SumActivity.java

import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;

public class SumActivity extends AppCompatActivity {
    private TextView sum_textView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sum_main);
        sum_textView = (TextView) findViewById(R.id.sum);
        Intent intent = getIntent();
        String x= intent.getStringExtra("x");
        String y= intent.getStringExtra("y");
        double xn = Double.parseDouble(intent.getStringExtra("x"));
        double yn = Double.parseDouble(intent.getStringExtra("y"));
        double su = xn+yn;
        sum_textView.setText(su+"");
    }
}

跳转时闪退处理

在
AndroidManifest.xml中注册

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.activityapp">
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.ActivityApp">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name=".SumActivity">
        </activity>
    </application>
</manifest>

成果展示

1.输入数字界面

2.求和界面

写作不易，点赞支撑，谢谢！