Android四大组件之Activity2-通过显式意图实现界面跳转

写了新的Activity要先在AndroidManifest.xml中注册

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.xrj.activitydemo">

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

    <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/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter> <!-- 哪写这个哪是入口-->
                <action android:name="android.intent.action.MAIN" />

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

        <activity android:name=".SecondActivity"/>
    </application>

</manifest>

MainActivity.java

package com.xrj.activitydemo;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;


public class MainActivity extends AppCompatActivity {

    private EditText maccount;
    private EditText mpasswprd;
    private Button mlogin;
    private static final String TAG = "MainActivity";


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        initListener();
    }

    private void initView() {
        maccount = (EditText) this.findViewById(R.id.account);
        mpasswprd = (EditText) this.findViewById(R.id.password);
        mlogin = this.findViewById(R.id.login);
    }

    private void initListener() {
        mlogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.d(TAG,"login click...");
                handlerLogin();
            }
        });
    }

    private void handlerLogin() {
        String accountText = maccount.getText().toString().trim();
        if(TextUtils.isEmpty(accountText)) {
            Toast.makeText(this,"输入的账号为空",Toast.LENGTH_SHORT).show();
        }
        String passwordText = mpasswprd.getText().toString().trim();
        if(TextUtils.isEmpty(passwordText)) {
            Toast.makeText(this,"输入的密码为空",Toast.LENGTH_SHORT).show();
        }
        //跳转
        Intent intent = new Intent(this,SecondActivity.class);
        intent.putExtra("account",accountText);//传数据
        intent.putExtra("password",passwordText);
        startActivity(intent);
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    tools:context=".MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="账号"
        android:textSize="35sp"/>

    <EditText
        android:id="@+id/account"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="密码"
        android:textSize="35sp"/>

    <EditText
        android:id="@+id/password"
        android:inputType="textPassword"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

    <Button
        android:id="@+id/login"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="登录"
        android:layout_gravity="center_horizontal"/>

</LinearLayout>

SecondActivity.java

package com.xrj.activitydemo;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

public class SecondActivity extends Activity {

    private static final String TAG = "SecondActivity";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);

        TextView info = (TextView) this.findViewById(R.id.info) ;

        Intent intent = getIntent();
        String account = intent.getStringExtra("account");
        String password = intent.getStringExtra("password");
        Log.d(TAG,"account==" + account);
        Log.d(TAG,"password==" + password);

        info.setText("您的账号是" + account + "    您的密码是：" + password);
    }
}

activity_second.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="登录信息如下"/>

    <TextView
        android:id="@+id/info"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>