public class MainActivity extends AppCompatActivity {
    private WebView wView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        wView = (WebView) findViewById(R.id.wView);
        wView.loadUrl("file:///android_asset/demo1.html");
        WebSettings webSettings = wView.getSettings();
        //①设置WebView允许调用js
        webSettings.setJavaScriptEnabled(true);
        webSettings.setDefaultTextEncodingName("UTF-8");
        //②将object对象暴露给Js,调用addjavascriptInterface
        wView.addJavascriptInterface(new MyObject(MainActivity.this), "myObj");
    }
}