鸿蒙JNI开发实战 原创 精华

package com.example.jnidemo;

public class JNITools {

   // 这个链接C语言文件的代码本来是在MainActivity里面，我挪到了这里来了，照做即可。
   static {
        System.loadLibrary("hello");
    }

		//自己添加加减乘除四个方法的声明，具体实现在native-lib.cpp文件里。
    public static native int addNumber(int a, int b);
    public static native int subNumber(int a, int b);
    public static native int mulNumber(int a, int b);
    public static native int divNumber(int a, int b);
}
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#include <jni.h>
#include <string>
#include <Hilog/log.h>

extern "C"
JNIEXPORT jint JNICALL
Java_com_example_jnidemo_JNITools_addNumber(JNIEnv* env, jobject obj, int a, int b) {
    return a+b;
}

extern "C"
JNIEXPORT jint JNICALL
Java_com_example_jnidemo_JNITools_subNumber(JNIEnv* env, jobject obj, int a, int b) {
    return a-b;
}

extern "C"
JNIEXPORT jint JNICALL
Java_com_example_jnidemo_JNITools_mulNumber(JNIEnv* env, jobject obj, int a, int b) {
    return a*b;
}

extern "C"
JNIEXPORT jint JNICALL
Java_com_example_jnidemo_JNITools_divNumber(JNIEnv* env, jobject obj, int a, int b) {
    return a/b;
}
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package com.example.jnidemo.slice;

import com.example.jnidemo.JNITools;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.components.PositionLayout;
import ohos.agp.components.Text;
import ohos.agp.utils.Color;
import ohos.agp.colors.RgbColor;
import ohos.agp.components.element.ShapeElement;
import ohos.agp.components.ComponentContainer.LayoutConfig;

public class MainAbilitySlice extends AbilitySlice {


    private PositionLayout myLayout = new PositionLayout(this);

    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        LayoutConfig config = new LayoutConfig(LayoutConfig.MATCH_PARENT, LayoutConfig.MATCH_PARENT);
        myLayout.setLayoutConfig(config);
        ShapeElement element = new ShapeElement();
        element.setShape(ShapeElement.RECTANGLE);
        element.setRgbColor(new RgbColor(255, 255, 255));
        myLayout.setBackground(element);
        Text text = new Text(this);

				//只有这一句代码需要自己写，测试一下加法的实现
        text.setText(String.format("%d", JNITools.addNumber(10, 20)));

        text.setTextColor(Color.BLACK);
        myLayout.addComponent(text);
        super.setUIContent(myLayout);
    }

    @Override
    public void onActive() {
        super.onActive();
    }

    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }

    /**
     * A native method that is implemented by the 'native-lib' native library,
     * which is packaged with this application.
     */
    //public native String stringFromJNI();
}

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//这个包名要和原来创建SO库文件工程的包名一样，而不是现在新工程的包名
//因为SO库里面的包名也是 package com.example.jnidemo
package com.example.jnidemo;

public class JNITools {

    static {
         System.loadLibrary("hello");
    }
    public static native int addNumber(int a, int b);
    public static native int subNumber(int a, int b);
    public static native int mulNumber(int a, int b);
    public static native int divNumber(int a, int b);
}
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import com.example.jnidemo.JNITools;
import com.example.sotest.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.components.Text;
import ohos.agp.utils.Color;

public class MainAbilitySlice extends AbilitySlice {
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main);

        Text text = (Text)findComponentById(ResourceTable.Id_text_helloworld);
        text.setText(" "+ JNITools.addNumber(20,10));
        text.setTextColor(Color.BLACK);
    }

    @Override
    public void onActive() {
        super.onActive();
    }

    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }
}

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