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Android之WebView显示PDF文档

发布时间 2023-10-31 13:42:24作者: 邢帅杰
参考：https://blog.csdn.net/Android_Cll/article/details/131641229
Android项目新增js：/app/src/main/assets/wwwroot/index.js 我新建了一个wwwroot放里面了。自己看着办。
var url = location.search.substring(1);

PDFJS.cMapUrl = 'https://unpkg.com/pdfjs-dist@1.9.426/cmaps/';
PDFJS.cMapPacked = true;

var pdfDoc = null;

function createPage() {
    var div = document.createElement("canvas");
    document.body.appendChild(div);
    return div;
}

function renderPage(num) {
    pdfDoc.getPage(num).then(function (page) {
        var viewport = page.getViewport(2.0);
        var canvas = createPage();
        var ctx = canvas.getContext('2d');

        canvas.height = viewport.height;
        canvas.width = viewport.width;

        page.render({
            canvasContext: ctx,
            viewport: viewport
        });
    });
}

PDFJS.getDocument(url).then(function (pdf) {
    pdfDoc = pdf;
    for (var i = 1; i <= pdfDoc.numPages; i++) {
        renderPage(i)
    }
});

同样目录，再新增一个index.html

<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width,initial-scale=1.0,minimum-scale=1.0,maximum-scale=4.0,user-scalable=no"/>
    <title>Document</title>
    <style type="text/css">
        canvas {
            width: 100%;
            height: 100%;
            border: 1px solid black;
        }
    </style>
    <script src="https://unpkg.com/pdfjs-dist@1.9.426/build/pdf.min.js"></script>
    <script type="text/javascript" src="index.js"></script>
</head>
<body>
</body>
</html>

webview加载pdf

package com.jay.myappstudy;

import android.app.Activity;
import android.content.Context;
import android.os.Build;
import android.os.Bundle;
import android.webkit.WebSettings;
import android.webkit.WebView;

public class WebViewPdfActivity extends Activity {
    private WebView mWv1;
    private Context ctx = this;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_web_view_pdf);
        mWv1 = findViewById(R.id.wv1);
        WebSettings webSettings = mWv1.getSettings();
        // 允许javascript 设置支持JS就自动打开IndexedDB存储机制
        webSettings.setJavaScriptEnabled(true);
        webSettings.setUseWideViewPort(true); //将图片调整到适合WebView的大小
        webSettings.setLoadWithOverviewMode(true);
        webSettings.setLoadWithOverviewMode(true); // 缩放至屏幕的大小
        webSettings.setLayoutAlgorithm(WebSettings.LayoutAlgorithm.NORMAL);
        webSettings.setUserAgentString("User-Agent");
        //webSettings.setLightTouchEnabled(true);//设置用鼠标激活被选项
        webSettings.setBuiltInZoomControls(true);//设置支持缩放
        webSettings.setDomStorageEnabled(true);//设置DOM缓存，当H5网页使用localStorage时，一定要设置
        webSettings.setDatabaseEnabled(true);
        //WebSettings.LOAD_NO_CACHE 设置去缓存，防止加载的为上一次加载过的
        webSettings.setCacheMode(WebSettings.LOAD_DEFAULT);
        webSettings.setSupportZoom(true);//设置支持变焦
        mWv1.setHapticFeedbackEnabled(false);
        //webSettings.setPluginState(WebSettings.PluginState.ON);
        webSettings.setAllowFileAccess(true);
        webSettings.setAllowContentAccess(true);
        // 设置是否允许通过 file url 加载的 Javascript 可以访问其他的源(包括http、https等源)
        webSettings.setAllowUniversalAccessFromFileURLs(true);
        // 支持通过JS打开新窗口
        webSettings.setAllowFileAccessFromFileURLs(true);
        webSettings.setDefaultTextEncodingName("UTF-8");
        webSettings.setJavaScriptCanOpenWindowsAutomatically(true);

        webSettings.setGeolocationEnabled(true);
        webSettings.setAppCacheEnabled(false);
        mWv1.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);

        //触摸焦点起作用
        mWv1.requestFocus();

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            //http与https的方法
            webSettings.setMixedContentMode(WebSettings.MIXED_CONTENT_ALWAYS_ALLOW);
        }
        mWv1.loadUrl("file:///android_asset/wwwroot/viewpdf.html?http://192.168.9.9:8090/1.pdf");
    }
}