Activity组件：（一）通过显式意图和隐式意图来实现Activity间的跳转

一、通过显式意图来实现Activity间的跳转

显式意图是指在创建Intent对象时就指定接受者组件

 /**

         * 下面是通过显式意图进行跳转，即明确写出要跳转到SecondActivity.class组件中去

         */

        Intent intent =new Intent(this,SecondActivity.class);

        intent.putExtra("account",account);

        intent.putExtra("password",password);

        startActivity(intent);

注意：创建Activity时要在manifests里进行静态注册，示例如下：

<activity android:name=".SecondActivity">

        </activity>

之后再要跳转到的界面接受Intent传递的内容

 //通过getIntent获取MainActivity传来的intent

        Intent intent = getIntent();

        String account = intent.getStringExtra("account");

        String password = intent.getStringExtra("password");

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二、通过隐式意图来实现Activity间的跳转

隐式意图就是通过intent过滤器来进行匹配跳转

 /**

         * 下面是通隐式意图进行跳转,要在manifests里添加意图过滤

         */

        Intent intent = new Intent();

        intent.setAction("com.example.activitydemo.LoginInfo");

        intent.addCategory(Intent.CATEGORY_DEFAULT);

        intent.putExtra("account",account);

        intent.putExtra("password",password);

        startActivity(intent);

进行注册的同时添加intent过滤

<activity android:name=".SecondActivity">

            <intent-filter>

                <action android:name="com.example.activitydemo.LoginInfo"/>

                <category  android:name="android.intent.category.DEFAULT"/>

            </intent-filter>

        </activity>

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三、原码

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.example.activitydemo">

    <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>

                <action android:name="android.intent.action.MAIN" />

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

            </intent-filter>

        </activity>

        <activity android:name=".SecondActivity">

            <intent-filter>

                <action android:name="com.example.activitydemo.LoginInfo"/>

                <category  android:name="android.intent.category.DEFAULT"/>

            </intent-filter>

        </activity>

    </application>

</manifest>

MainActivity.java

package com.example.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 static final String TAG = "MainActivity";

    private EditText mAccount;

    private EditText mPassword;

    private Button mLogin;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        initView();

        initListener();

    }

    private void initListener() {

        mLogin.setOnClickListener(new View.OnClickListener() {

            @Override

            public void onClick(View v) {

                //登录按钮被点击了

                Log.d(TAG,"Login Click。。。");

                handlerLogin();

            }

        });

    }

    private void handlerLogin() {

        //.trim()用于去空格

        String account = mAccount.getText().toString().trim();

        if (TextUtils.isEmpty(account)) {

            Toast.makeText(this,"输入的账号为空",Toast.LENGTH_SHORT).show();

            return;

        }

        String password = mPassword.getText().toString().trim();

        if (TextUtils.isEmpty(password)) {

            Toast.makeText(this,"输入的密码为空",Toast.LENGTH_SHORT).show();;

        }

        //先要创建一个意图对象，然后通过StartActivity()来实现跳转

        /**

         * 下面是通过显式意图进行跳转，即明确写出要跳转到SecondActivity.class组件中去

         */

//        Intent intent =new Intent(this,SecondActivity.class);

//        intent.putExtra("account",account);

//        intent.putExtra("password",password);

//        startActivity(intent);

        /**

         * 下面是通隐式意图进行跳转,要在manifests里添加意图过滤

         */

        Intent intent = new Intent();

        intent.setAction("com.example.activitydemo.LoginInfo");

        intent.addCategory(Intent.CATEGORY_DEFAULT);

        intent.putExtra("account",account);

        intent.putExtra("password",password);

        startActivity(intent);

    }

    private void initView() {

        mAccount = (EditText) this.findViewById(R.id.account);

        mPassword = (EditText) this.findViewById(R.id.password);

        mLogin = (Button)  this.findViewById(R.id.login);

    }

}

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:text="登录"

        android:textSize="30sp"

        android:layout_gravity="center"

        android:layout_height="wrap_content">

    </TextView>

    <TextView

        android:layout_width="wrap_content"

        android:text="账号："

        android:textSize="25sp"

        android:layout_height="wrap_content">

    </TextView>

    <EditText

        android:id="@+id/account"

        android:layout_width="match_parent"

        android:layout_height="wrap_content">

    </EditText>

    <TextView

        android:layout_width="wrap_content"

        android:text="密码："

        android:textSize="25sp"

        android:layout_height="wrap_content">

    </TextView>

    <EditText

        android:id="@+id/password"

        android:layout_width="match_parent"

        android:inputType="textPassword"

        android:layout_height="wrap_content">

    </EditText>

    <Button

        android:id="@+id/login"

        android:layout_width="match_parent"

        android:text="登录"

        android:layout_height="wrap_content">

    </Button>

</LinearLayout>

SecondActivity.java

package com.example.activitydemo;

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.widget.TextView;

import androidx.annotation.Nullable;

public class SecondActivity extends Activity {

    @Override

    protected void onCreate(@Nullable Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_second);

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

        //通过getIntent获取MainActivity传来的intent

        Intent intent = getIntent();

        String account = intent.getStringExtra("account");

        String password = intent.getStringExtra("password");

        info.setText("您的账号为："+account+"您的密码为："+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="match_parent"

        android:text="登录信息如下："

        android:layout_marginTop="20dp"

        android:textSize="20sp"

        android:layout_height="wrap_content">

    </TextView>

    <TextView

        android:id="@+id/info"

        android:layout_width="match_parent"

        android:textSize="25sp"

        android:text=""

        android:layout_height="wrap_content">

    </TextView>

</LinearLayout>