更新 README.md
parent
23b0e31045
commit
02a849272a
|
|
@ -1,190 +1,190 @@
|
|||
# 安卓APP
|
||||
|
||||
## 目的
|
||||
|
||||
1. 实现页面按钮跳转页面
|
||||
2. 点击按钮后，页面显示来自JNI的字符串
|
||||
|
||||
## 实验步骤
|
||||
|
||||
### 1. 准备开发环境
|
||||
|
||||
- Android Studio
|
||||
- JDK
|
||||
- NDK（创建项目时会自动部署）
|
||||
- CMake（创建项目时会自动部署）
|
||||
|
||||
### 2. 创建一个原生C++安卓项目
|
||||
|
||||
|
||||
|
||||
> 部署原生C++安卓项目时，路径中不能有空格
|
||||
>
|
||||
> 使用了API 28: Android 9.0
|
||||
|
||||
### 3. 主页面添加按钮
|
||||
|
||||
在`MainActivity.java`中添加一个按钮，点击后跳转到`SecondActivity`
|
||||
|
||||
```
|
||||
package com.example.jnidemoapp;
|
||||
|
||||
import android.content.Intent;
|
||||
import android.os.Bundle;
|
||||
import android.view.View;
|
||||
import android.widget.Button;
|
||||
import androidx.appcompat.app.AppCompatActivity;
|
||||
|
||||
public class MainActivity extends AppCompatActivity {
|
||||
@Override
|
||||
protected void onCreate(Bundle savedInstanceState) {
|
||||
super.onCreate(savedInstanceState);
|
||||
setContentView(R.layout.activity_main);
|
||||
|
||||
// 页面跳转按钮
|
||||
Button button = findViewById(R.id.button_go_to_second);
|
||||
button.setOnClickListener(new View.OnClickListener() {
|
||||
@Override
|
||||
public void onClick(View v) {
|
||||
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
|
||||
startActivity(intent);
|
||||
}
|
||||
});
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### 4. 创建SecondActivity.java
|
||||
|
||||
新建`SecondActivity.java`文件，显示来自JNI的字符串
|
||||
|
||||
```
|
||||
package com.example.jnidemoapp;
|
||||
|
||||
import android.os.Bundle;
|
||||
import android.widget.TextView;
|
||||
import androidx.appcompat.app.AppCompatActivity;
|
||||
|
||||
public class SecondActivity extends AppCompatActivity {
|
||||
|
||||
// 加载本地库
|
||||
static {
|
||||
System.loadLibrary("jnidemoapp");
|
||||
}
|
||||
|
||||
// 声明一个本地方法
|
||||
public native String stringFromJNI();
|
||||
|
||||
@Override
|
||||
protected void onCreate(Bundle savedInstanceState) {
|
||||
super.onCreate(savedInstanceState);
|
||||
setContentView(R.layout.activity_second);
|
||||
|
||||
// 显示 JNI 返回的字符串
|
||||
TextView textView = findViewById(R.id.text_jni_string);
|
||||
textView.setText(stringFromJNI());
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### 5. 调整界面布局
|
||||
|
||||
- 在`activity_main.xml`中添加一个按钮：
|
||||
```
|
||||
<?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">
|
||||
|
||||
<Button
|
||||
android:id="@+id/button_go_to_second"
|
||||
android:layout_width="wrap_content"
|
||||
android:layout_height="wrap_content"
|
||||
android:text="跳转"
|
||||
android:layout_centerInParent="true"/>
|
||||
</RelativeLayout>
|
||||
```
|
||||
|
||||
- 在 `activity_second.xml` 添加一个 `TextView`：
|
||||
```
|
||||
<?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">
|
||||
|
||||
<TextView
|
||||
android:id="@+id/text_jni_string"
|
||||
android:layout_width="wrap_content"
|
||||
android:layout_height="wrap_content"
|
||||
android:text="等待JNI数据..."
|
||||
android:textSize="18sp"
|
||||
android:layout_centerInParent="true"/>
|
||||
</RelativeLayout>
|
||||
```
|
||||
|
||||
### 6. 添加JNI字符串
|
||||
|
||||
- 配置`CMakeLists.txt`文件
|
||||
|
||||
```
|
||||
# For more information about using CMake with Android Studio, read the
|
||||
# documentation: https://d.android.com/studio/projects/add-native-code.html
|
||||
|
||||
# Sets the minimum version of CMake required to build the native library.
|
||||
|
||||
cmake_minimum_required(VERSION 3.22.1)
|
||||
|
||||
# Declares and names the project.
|
||||
|
||||
project("jnidemoapp")
|
||||
|
||||
# Creates and names a library, sets it as either STATIC
|
||||
# or SHARED, and provides the relative paths to its source code.
|
||||
# You can define multiple libraries, and CMake builds them for you.
|
||||
# Gradle automatically packages shared libraries with your APK.
|
||||
|
||||
add_library( # Sets the name of the library.
|
||||
jnidemoapp
|
||||
|
||||
# Sets the library as a shared library.
|
||||
SHARED
|
||||
|
||||
# Provides a relative path to your source file(s).
|
||||
native-lib.cpp)
|
||||
|
||||
# Searches for a specified prebuilt library and stores the path as a
|
||||
# variable. Because CMake includes system libraries in the search path by
|
||||
# default, you only need to specify the name of the public NDK library
|
||||
# you want to add. CMake verifies that the library exists before
|
||||
# completing its build.
|
||||
|
||||
find_library( # Sets the name of the path variable.
|
||||
log-lib
|
||||
|
||||
# Specifies the name of the NDK library that
|
||||
# you want CMake to locate.
|
||||
log)
|
||||
|
||||
# Specifies libraries CMake should link to your target library. You
|
||||
# can link multiple libraries, such as libraries you define in this
|
||||
# build script, prebuilt third-party libraries, or system libraries.
|
||||
|
||||
target_link_libraries( # Specifies the target library.
|
||||
jnidemoapp
|
||||
|
||||
# Links the target library to the log library
|
||||
# included in the NDK.
|
||||
${log-lib})
|
||||
```
|
||||
|
||||
> 这里的库名称需要和SecondActivity.java中的System.loadLibrary函数中的库名称对应
|
||||
|
||||
### 7. 编译运行模拟器，并测试
|
||||
|
||||
- 起始页面：
|
||||
|
||||
|
||||
|
||||
- 点击按钮后：
|
||||
|
||||
# 安卓APP
|
||||
|
||||
## 目的
|
||||
|
||||
1. 实现页面按钮跳转页面
|
||||
2. 点击按钮后，页面显示来自JNI的字符串
|
||||
|
||||
## 实验步骤
|
||||
|
||||
### 1. 准备开发环境
|
||||
|
||||
- Android Studio
|
||||
- JDK
|
||||
- NDK（创建项目时会自动部署）
|
||||
- CMake（创建项目时会自动部署）
|
||||
|
||||
### 2. 创建一个原生C++安卓项目
|
||||
|
||||
|
||||
|
||||
> 部署原生C++安卓项目时，路径中不能有空格
|
||||
>
|
||||
> 使用了API 28: Android 9.0
|
||||
|
||||
### 3. 主页面添加按钮
|
||||
|
||||
在`MainActivity.java`中添加一个按钮，点击后跳转到`SecondActivity`
|
||||
|
||||
```
|
||||
package com.example.jnidemoapp;
|
||||
|
||||
import android.content.Intent;
|
||||
import android.os.Bundle;
|
||||
import android.view.View;
|
||||
import android.widget.Button;
|
||||
import androidx.appcompat.app.AppCompatActivity;
|
||||
|
||||
public class MainActivity extends AppCompatActivity {
|
||||
@Override
|
||||
protected void onCreate(Bundle savedInstanceState) {
|
||||
super.onCreate(savedInstanceState);
|
||||
setContentView(R.layout.activity_main);
|
||||
|
||||
// 页面跳转按钮
|
||||
Button button = findViewById(R.id.button_go_to_second);
|
||||
button.setOnClickListener(new View.OnClickListener() {
|
||||
@Override
|
||||
public void onClick(View v) {
|
||||
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
|
||||
startActivity(intent);
|
||||
}
|
||||
});
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### 4. 创建SecondActivity.java
|
||||
|
||||
新建`SecondActivity.java`文件，显示来自JNI的字符串
|
||||
|
||||
```
|
||||
package com.example.jnidemoapp;
|
||||
|
||||
import android.os.Bundle;
|
||||
import android.widget.TextView;
|
||||
import androidx.appcompat.app.AppCompatActivity;
|
||||
|
||||
public class SecondActivity extends AppCompatActivity {
|
||||
|
||||
// 加载本地库
|
||||
static {
|
||||
System.loadLibrary("jnidemoapp");
|
||||
}
|
||||
|
||||
// 声明一个本地方法
|
||||
public native String stringFromJNI();
|
||||
|
||||
@Override
|
||||
protected void onCreate(Bundle savedInstanceState) {
|
||||
super.onCreate(savedInstanceState);
|
||||
setContentView(R.layout.activity_second);
|
||||
|
||||
// 显示 JNI 返回的字符串
|
||||
TextView textView = findViewById(R.id.text_jni_string);
|
||||
textView.setText(stringFromJNI());
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
### 5. 调整界面布局
|
||||
|
||||
- 在`activity_main.xml`中添加一个按钮：
|
||||
```
|
||||
<?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">
|
||||
|
||||
<Button
|
||||
android:id="@+id/button_go_to_second"
|
||||
android:layout_width="wrap_content"
|
||||
android:layout_height="wrap_content"
|
||||
android:text="跳转"
|
||||
android:layout_centerInParent="true"/>
|
||||
</RelativeLayout>
|
||||
```
|
||||
|
||||
- 在 `activity_second.xml` 添加一个 `TextView`：
|
||||
```
|
||||
<?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">
|
||||
|
||||
<TextView
|
||||
android:id="@+id/text_jni_string"
|
||||
android:layout_width="wrap_content"
|
||||
android:layout_height="wrap_content"
|
||||
android:text="等待JNI数据..."
|
||||
android:textSize="18sp"
|
||||
android:layout_centerInParent="true"/>
|
||||
</RelativeLayout>
|
||||
```
|
||||
|
||||
### 6. 添加JNI字符串
|
||||
|
||||
- 配置`CMakeLists.txt`文件
|
||||
|
||||
```
|
||||
# For more information about using CMake with Android Studio, read the
|
||||
# documentation: https://d.android.com/studio/projects/add-native-code.html
|
||||
|
||||
# Sets the minimum version of CMake required to build the native library.
|
||||
|
||||
cmake_minimum_required(VERSION 3.22.1)
|
||||
|
||||
# Declares and names the project.
|
||||
|
||||
project("jnidemoapp")
|
||||
|
||||
# Creates and names a library, sets it as either STATIC
|
||||
# or SHARED, and provides the relative paths to its source code.
|
||||
# You can define multiple libraries, and CMake builds them for you.
|
||||
# Gradle automatically packages shared libraries with your APK.
|
||||
|
||||
add_library( # Sets the name of the library.
|
||||
jnidemoapp
|
||||
|
||||
# Sets the library as a shared library.
|
||||
SHARED
|
||||
|
||||
# Provides a relative path to your source file(s).
|
||||
native-lib.cpp)
|
||||
|
||||
# Searches for a specified prebuilt library and stores the path as a
|
||||
# variable. Because CMake includes system libraries in the search path by
|
||||
# default, you only need to specify the name of the public NDK library
|
||||
# you want to add. CMake verifies that the library exists before
|
||||
# completing its build.
|
||||
|
||||
find_library( # Sets the name of the path variable.
|
||||
log-lib
|
||||
|
||||
# Specifies the name of the NDK library that
|
||||
# you want CMake to locate.
|
||||
log)
|
||||
|
||||
# Specifies libraries CMake should link to your target library. You
|
||||
# can link multiple libraries, such as libraries you define in this
|
||||
# build script, prebuilt third-party libraries, or system libraries.
|
||||
|
||||
target_link_libraries( # Specifies the target library.
|
||||
jnidemoapp
|
||||
|
||||
# Links the target library to the log library
|
||||
# included in the NDK.
|
||||
${log-lib})
|
||||
```
|
||||
|
||||
> 这里的库名称需要和SecondActivity.java中的System.loadLibrary函数中的库名称对应
|
||||
|
||||
### 7. 编译运行模拟器，并测试
|
||||
|
||||
- 起始页面：
|
||||
|
||||
|
||||
|
||||
- 点击按钮后：
|
||||
|
||||
|
||||
Loading…
Reference in New Issue