Android WebView的使用方法总结

 Android WebView的使用方法

Android app打开H5页一般要实现如下需求：

1、打开指定url网页；
2、点击链接可以跳转到下一页，并更新标题；
3、按back键或左箭头可以返回上一页；
4、当webview显示的是第一级url时， 按返回键或左箭头关闭当前界面；
5、WebView如何传值给android， 例如使用H5登录成功后返回姓名、token等等字段。
6、支持JavaScript， 支持显示js对话框。
7、无网络时显示默认布局， 以提高用户体验。
8、避免WebView的内存泄漏。

不多说， 看下面代码如何实现上述功能。

参考布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:my="http://schemas.android.com/apk/res-auto"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:background="@color/activity_main_bg"
  android:orientation="vertical">

  <com.eloancn.borrower.common.widget.TitleView
    android:id="@+id/titleView"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    my:titleText="H5" />

  <RelativeLayout
    android:id="@+id/rl_webViewContainer"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <!--在代码中添加webView防止内存泄露隐患-->

    <LinearLayout
      android:id="@+id/neterror_tip"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:gravity="center_horizontal"
      android:visibility="gone">

      <ImageView
        android:layout_marginTop="110dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/not_found" />

    </LinearLayout>

  </RelativeLayout>
</LinearLayout>

示例代码：

public class CommonWebViewActivity extends Activity {
  private WebView mWebView;
  private TitleView mTitleView;
  private RelativeLayout mWebViewContainer;
  private String title;
  private String url;
  private LinearLayout neterrorLayout;
  private int mFlag;  //来源 

  public static final int FLAG_SIGNATURE = 1; 

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_common_webview_main);
    initData();
    initView();
    setData();
  } 

  @Override
  protected void onDestroy() {
    super.onDestroy();
    mWebView.setWebViewClient(null);
    mWebView.setWebChromeClient(null);
    mWebViewContainer.removeView(mWebView);
    mWebView.removeAllViews();
    mWebView.destroy();
  } 

  private void initData() {
    url = getIntent().getStringExtra("url");
    title = getIntent().getStringExtra("title");
    mFlag = getIntent().getIntExtra("flag", 0);
  } 

  private void initView() {
    mTitleView = (TitleView) findViewById(R.id.titleView);
    mWebViewContainer = (RelativeLayout) findViewById(R.id.rl_webViewContainer);
    neterrorLayout = (LinearLayout) findViewById(R.id.neterror_tip);
    mWebView = new WebView(getApplicationContext());
    LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
        LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);
    mWebViewContainer.addView(mWebView, layoutParams); 

    WebSettings webSettings = mWebView.getSettings();
    //设置WebView属性，能够执行Javascript脚本
    webSettings.setJavaScriptEnabled(true);
    //设置可以访问文件
    webSettings.setAllowFileAccess(true);
    //设置支持缩放
    webSettings.setBuiltInZoomControls(false);
    //允许js弹出窗口
    webSettings.setJavaScriptCanOpenWindowsAutomatically(true); 

    mTitleView.setLeftBtnClickListener(new TitleView.OnBtnClickListener() {
      @Override
      public void onClick(View v) {
        if (mWebView.canGoBack()) {
          mWebView.goBack();
        } else {
          finish();
        }
      }
    });
  } 

  @Override
  public boolean onKeyDown(int keyCode, KeyEvent event) {
    if (keyCode == KeyEvent.KEYCODE_BACK) {
      if (mWebView.canGoBack()) {
        mWebView.goBack();
        return true;
      }
    }
    return super.onKeyDown(keyCode, event);
  } 

  private void setData() {
    mTitleView.setTitle(title);
    mWebView.loadUrl(url); 

    mWebView.setWebChromeClient(new WebChromeClient(){
      @Override
      public boolean onJsAlert(WebView view, String url, final String message, final JsResult result) {
        //注意，WebView默认不会显示JavaScript的Alert，需要Android实现。
        runOnUiThread(new Runnable() {
          @Override
          public void run() {
            //自定义美观的Dialog，仅仅是为了显示message
            CustomDialog.Builder builder = new CustomDialog.Builder(CommonWebViewActivity.this);
            builder.setTitle("提示");
            builder.setMessage(message);
            builder.setSingle("知道了", new DialogInterface.OnClickListener() {
              @Override
              public void onClick(DialogInterface dialogInterface, int i) {
                dialogInterface.dismiss();
              }
            });
            builder.create().show();
          }
        });
        result.confirm();//这里必须调用，否则页面会阻塞造成假死
        return true;
      } 

      @Override
      public void onReceivedTitle(final WebView view, final String title) {
        super.onReceivedTitle(view, title);
        if (FLAG_SIGNATURE == mFlag) {
          runOnUiThread(new Runnable() {
            @Override
            public void run() {
              mTitleView.setTitle(title);
            }
          });
        }
      }
    });
    mWebView.setWebViewClient(new WebViewClient() {
      @Override
      public WebResourceResponse shouldInterceptRequest(WebView view, WebResourceRequest request) {
        if (FLAG_SIGNATURE == mFlag) {
          Log.d("brycegao", "shouldInterceptRequest url:" + request.getUrl().toString());
          if (request.getUrl().toString().contains("wxd://getImage?tenderid=")) {
            //可以通过url传值给Android， 即在url里放置想要的参数
            runOnUiThread(new Runnable() {
              @Override
              public void run() {
                setResult(RESULT_OK);
                finish();
              }
            });
          } 

        }
        return super.shouldInterceptRequest(view, request);
      } 

      @Override
      public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
        mWebView.loadUrl(url);
        return true;
      } 

      @Override
      public void onReceivedError(WebView view, WebResourceRequest request, WebResourceError error) {
        super.onReceivedError(view, request, error); 

        if (FLAG_SIGNATURE == mFlag
            && request.getUrl().toString().contains("wxd://getImage?tenderid=")) {
          //do nothing
          mWebView.setVisibility(View.GONE); //优化体验，避免显示错误信息
        } else {
          //加载失败
          neterrorLayout.setVisibility(View.VISIBLE);
          mWebView.setVisibility(View.GONE);
        }
      }
    }); 

    neterrorLayout.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View view) {
        mWebView.setVisibility(View.VISIBLE);
        neterrorLayout.setVisibility(View.GONE);
        mWebView.loadUrl(url);
      }
    });
  }
}

以上就是Android Webview的使用方法详解，大家如果有疑问可以留言讨论，或者到本站社区交流，感谢阅读，希望能帮助到大家，谢谢大家对本站的支持！