1.在Activity中编写native方法
package com.godv.ccalljava;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void showToa(View view) {
toastCallBack();
}
public native void toastCallBack();
public void showToast(){
Log.i("godv","更新UI");
Toast.makeText(this, "godv", Toast.LENGTH_SHORT).show();
}
}
2.生成 .h 文件 重写 .c 中的方法
JNIEXPORT void JNICALL Java_com_godv_ccalljava_MainActivity_toastCallBack
(JNIEnv * env, jobject instance)
{
jclass jclazz = (*env)->FindClass(env,"com/godv/ccalljava/MainActivity");
jmethodID jids = (*env)->GetMethodID(env,jclazz,"showToast","()V");
(*env)->CallVoidMethod(env,instance,jids);
}
3.在activity调用