如何在Android应用程序中Activity之间传递数据?
本例演示如何在Android应用程序中Activity之间传递数据。
步骤 1 − 在Android Studio中创建一个新项目,转到文件 ⇒ 新建项目,并填写所有必需的详细信息以创建新项目。
步骤 2 − 将以下代码添加到res/layout/activity_main.xml。
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:id="@+id/activity_first" android:paddingTop="60dp" tools:context=".FirstActivity"> <LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical"> <LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:paddingLeft="10sp"> <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="0.25"/> <EditText android:id="@+id/editTxtName" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="0.75" android:ems="10" /> </LinearLayout> <LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:paddingLeft="10sp" android:paddingTop="16dp"> <TextView android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="0.25" /> <Spinner android:id="@+id/ageGroupSpinner" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_gravity="center_vertical" android:layout_weight="0.75"/> </LinearLayout> <LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:paddingTop="16dp"> <View android:layout_width="0dp" android:layout_height="match_parent" android:layout_weight="0.50" /> <Button android:id="@+id/btnSubmit" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_weight="0.20"/> </LinearLayout> </LinearLayout> </RelativeLayout>
步骤 3 − 将以下代码添加到res/layout/activity_second.xml
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:id="@+id/activity_second" android:paddingTop="60dp"> <LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="vertical"> <LinearLayout android:layout_width="fill_parent" android:layout_height="wrap_content" android:orientation="horizontal" android:paddingLeft="10sp"> <TextView android:id="@+id/displayMsg" android:layout_width="0dp" android:layout_height="wrap_content" android:layout_weight="0.25" /> </LinearLayout> </LinearLayout> </RelativeLayout>
步骤 4 − 将以下代码添加到src/MainActivity.java
package com.example.sample; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.content.Intent; import android.view.View; import android.widget.AdapterView; import android.widget.Button; import android.widget.EditText; import android.widget.Spinner; import android.widget.Toast; public class FirstActivity extends AppCompatActivity { Button btnSubmit = null; EditText editTxtName = null; private static final String STING_EMPTY = ""; private static int ageGroup = 0; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_first); btnSubmit = (Button) findViewById(R.id.btnSubmit); btnSubmit.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { editTxtName = (EditText) findViewById(R.id.editTxtName); if (STING_EMPTY.equals(editTxtName.getText().toString())) { Toast.makeText(FirstActivity.this, "Name Cannot be empty!", Toast.LENGTH_LONG).show(); } else { Spinner ageGroupSpinner = (Spinner)findViewById(R.id.ageGroupSpinner); ageGroupSpinner.setOnItemSelectedListener( new AdapterView.OnItemSelectedListener() { @Override public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) { //set the corresponding age group when the user changes // the age group from dropdown ageGroup = i; } @Override public void onNothingSelected(AdapterView<?> adapterView) { } }); //Create a new intent for the SecondActivity Intent i = new Intent(FirstActivity.this,SecondActivity.class); //Populate the input values in a bundle and pass it to SecondActivity Bundle b = new Bundle(); b.putString("name",editTxtName.getText().toString()); b.putInt("ageGroup",ageGroup); //Set the userBundle to the intent i.putExtra("userBundle",b); startActivity(i); } } }); } }
步骤 5 − 将以下代码添加到src/SecondActivity.java
package com.example.sample; import android.content.Intent; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.v7.app.AppCompatActivity; import android.widget.TextView; public class SecondActivity extends AppCompatActivity { @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_second); //get the passed intent Intent i = getIntent(); //get the bundle stored inside the intent Bundle b = i.getBundleExtra("userBundle"); TextView displayMsg = (TextView) findViewById(R.id.displayMsg); String message = "Hi, " + b.getString("name") + " "; int ageGroup = b.getInt("ageGroup"); switch (ageGroup){ case 0: message = message + "Enjoy your life"; break; case 1: message = message + "Don't take life too seriously.. Have fun!"; break; case 2: message = message + "Celebrate your life with old memories!"; break; } displayMsg.setText(message); } }
步骤 6 − 将以下代码添加到Manifests/AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.sample"> <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=".FirstActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name=".SecondActivity"></activity> </application> </manifest>
让我们尝试运行您的应用程序。我假设您已将实际的Android移动设备连接到计算机。要从Android Studio运行应用程序,请打开项目的一个Activity文件,然后单击运行 工具栏中的图标。选择您的移动设备作为选项,然后检查您的移动设备,它将显示您的默认屏幕 –
点击 这里 下载项目代码。
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