WebView相關研究

public class MainActivity extends AppCompatActivity {

private WebView webView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    //全屏
    this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    //禁止休眠
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON, WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

    webView = (WebView)findViewById(R.id.web);
    // 如果頁面中鏈接，如果希望點擊鏈接繼續在當前browser中響應，
    // 而不是新開Android的系統browser中響應該鏈接，必須覆蓋webview的WebViewClient對象
    webView.setWebViewClient(new WebViewClient() {
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            //  重寫此方法表明點擊網頁裏面的鏈接還是在當前的webview裏跳轉，不跳到瀏覽器那邊
            view.loadUrl(url);
            return true;
        }
    });
    //點擊後退按鈕,讓WebView後退一頁(也可以覆寫Activity的onKeyDown方法)
    webView.setOnKeyListener(new View.OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {
            if (event.getAction() == KeyEvent.ACTION_DOWN) {
                if (keyCode == KeyEvent.KEYCODE_BACK && webView.canGoBack()) {  //表示按返回鍵

                    webView.goBack();   //後退

                    //webview.goForward();//前進
                    return true;    //已處理
                }
            }
            return false;
        }
    });

    webView.loadUrl("http://edu.5ge.cn/dp");
    webView.getSettings().setJavaScriptEnabled(true);
    webView.getSettings().setAppCacheEnabled(true);
    //設置緩存模式
    webView.getSettings().setCacheMode(WebSettings.LOAD_DEFAULT);

// //爲25%，最小縮放等級 ，可以在這裏根據需求來設置縮放比例.
// webView.setInitialScale(80);

// int screenDensity = getResources().getDisplayMetrics().densityDpi ;
// WebSettings.ZoomDensity zoomDensity = WebSettings.ZoomDensity.MEDIUM ;
// switch (screenDensity){
// case DisplayMetrics.DENSITY_LOW :
// zoomDensity = WebSettings.ZoomDensity.CLOSE;
// break;
// case DisplayMetrics.DENSITY_MEDIUM:
// zoomDensity = WebSettings.ZoomDensity.MEDIUM;
// break;
// case DisplayMetrics.DENSITY_HIGH:
// zoomDensity = WebSettings.ZoomDensity.FAR;
// case DisplayMetrics.DENSITY_TV:
// zoomDensity = WebSettings.ZoomDensity.;
// break ;
// }

// webView.getSettings().setUseWideViewPort(true);//讓webview讀取網頁設置的viewport，pc版網頁//
// webView.getSettings().setLoadWithOverviewMode(true);

    webView.getSettings().setLayoutAlgorithm(WebSettings.LayoutAlgorithm.NARROW_COLUMNS);//適應內容大小//
    webView.getSettings().setLayoutAlgorithm(WebSettings.LayoutAlgorithm.SINGLE_COLUMN);//適應屏幕，內容將自動縮放
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {

    // TODO Auto-generated method stub

    super.onCreateOptionsMenu(menu);

    int group1 = 1;

    int group2 = 2;

    menu.add(group1, 1, 1, "刷新");

    return true;

}

@Override

public boolean onOptionsItemSelected(MenuItem item) {

    // TODO Auto-generated method stub

    switch (item.getItemId()) {

        case 1: // do something here

            webView.reload();

            break;

        default:

            return super.onOptionsItemSelected(item);

    }
    return true;

}

}