147 lines
3.8 KiB
Markdown
147 lines
3.8 KiB
Markdown
### 安卓app操作文档
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#### 一、实现目标
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1. 实现页面按钮跳转页面
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2. 点击按钮后，页面显示来自JNI的字符串
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#### 二、环境搭建
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2.1 jdk安装
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2.2 andriod studio 安装
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#### 三、具体实现
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3.1 设置页面跳转
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为了实现跳转页面，首先需要创建两个活动：（`MainActivity`主页面）和`SecondActivity`（跳转后的页面）
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3.11 MainActivity
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```
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package com.example.myapplication;
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import android.content.Intent;
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import android.os.Bundle;
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import android.view.View;
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import android.widget.Button;
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import androidx.appcompat.app.AppCompatActivity;
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public class MainActivity extends AppCompatActivity {
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@Override
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protected void onCreate(Bundle savedInstanceState) {
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super.onCreate(savedInstanceState);
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setContentView(R.layout.activity_main);
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Button btnNavigate = findViewById(R.id.btnNavigate);
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// 设置按钮点击事件，跳转到SecondActivity
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btnNavigate.setOnClickListener(new View.OnClickListener() {
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@Override
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public void onClick(View v) {
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Intent intent = new Intent(MainActivity.this, SecondActivity.class);
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startActivity(intent);
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}
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});
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}
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}
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```
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3.12 SecondActivity
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```
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package com.example.myapplication;
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import android.os.Bundle;
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import android.view.View;
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import android.widget.Button;
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import android.widget.TextView;
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import androidx.appcompat.app.AppCompatActivity;
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public class SecondActivity extends AppCompatActivity {
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static {
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System.loadLibrary("native-lib"); // 加载JNI库
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}
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// 声明JNI方法
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private native String getJNIString();
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@Override
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protected void onCreate(Bundle savedInstanceState) {
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super.onCreate(savedInstanceState);
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setContentView(R.layout.activity_second);
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Button btnShowJNI = findViewById(R.id.btnShowJNI);
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TextView textViewFromJNI = findViewById(R.id.jniTextView);
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// 设置按钮点击事件，获取并显示JNI字符串
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btnShowJNI.setOnClickListener(new View.OnClickListener() {
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@Override
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public void onClick(View v) {
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// 调用JNI方法并显示结果
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textViewFromJNI.setText(getJNIString());
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}
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});
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}
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}
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```
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3.2 集成JNI
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3.21 在`native-lib.cpp`中，编写JNI方法以返回字符串
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```
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#include <jni.h>
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#include <string>
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extern "C" JNIEXPORT jstring JNICALL
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Java_com_example_myapplication_SecondActivity_getJNIString(JNIEnv* env, jobject /* this */) {
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std::string hello = "Hello from JNI!";
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return env->NewStringUTF(hello.c_str());
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}
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```
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3.22 CMakeLists.txt编写
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```
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cmake_minimum_required(VERSION 3.10.2)
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# Set project name
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project("myapplication")
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# Set the path for the source file (make sure the path is correct)
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add_library(native-lib SHARED E:/CodeProject/AndroidProjects/MyApplication/app/src/main/cpp/native-lib.cpp)
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# Find the log library (important for Android projects)
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find_library( log-lib
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log )
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# Link the native library with the log library
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target_link_libraries( native-lib
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${log-lib} )
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```
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#### 四、运行结果
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4.1 初始运行界面
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点击Page Jump跳转到第二页面
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4.2 验证跳转功能
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点击Show JNI String 按钮，成功显示“Hello from JNI!”
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